The system is clever enough to join the two sections of your journey together so you would end up paying peak fare throughout if you don't find a way to split at Paddington.

Conversely if you enter during the off peak time it will be better to stick to one card as the whole journey will remain off peak.

Yes the contactless payment method is cheaper, by a large margin if you tap in during off-peak.
The only other thing to be cautious of is since the contactless is timed based on entry so you would need to tap in at 19:01 or later to get the off-peak fare. If finely timed you could use an oyster card to go from Liverpool Street to Paddington then Contactless from Paddington at 19:01, effectively a different type of split ticket to ensure your departure from London is charged at the lower Off-Peak rate.

The only other thing to watch out for is since your London Paddington to Reading section occurs after morning peak it could be worth investigating using a ticket with a railcard discount if you do find that section to be in the evening peak.

The train I was on just after 7am from Paddington towards Abbey Wood carried two bicycles

TfL^» (Transport for London - about) have recently put 7020 on Furlough for an initial 3 week period if that helps your calculation

You could switch like Crossrail from a signaller to a Traffic Manager they can then hold Signalling and Electrical skills.
But more fundamentally switching is ideally minimised to protect the switching equipment.
In terms of safety until proven and locked off no-one should be working near a bare conductor e.g. third rail so procedurally it wouldn't matter if it was switched on or off after each train.

Since IET^▸ (Intercity Express Train) introduction its been almost guaranteed that sitting in first class results in a ticket check between Reading and Paddington or v.v.

HSTs^▸ (High Speed Train) from Paddington almost always get a ticket check but not v.v.
Turbo's I can't remember the last time I used one and there was a ticket check.

Reading to Paddington in the morning and Paddington to Reading in the evening you'll find all the first class full and on occassions I've seen customers turned away.
Those carriages thus subsidise the balance of the train.

Customer information displays and announcements are normally set to display/announce the position but it seems that isn't quite enough for the crowd that like to ignore both

Is it possible the trolley confusion comes from the early days of IET^▸ (Intercity Express Train) operation, the first class trolley was then used but now is a galley cart is used so has the change already come but is only relevant to first class?

GWR^▸ (Great Western Railway) probably wouldn't be interested its not their station it being a station operated by TfL^» (Transport for London - about) Rail and cared for by the Freeholder Network Rail but you can report the problem via either:

1st choice = https://tfl.gov.uk/help-and-contact/contact-us-about-tube-and-rail (select TfL Rail)
or
2nd choice = https://www.networkrail.co.uk/communities/contact-us/

Next week the Route 17 bus route gets Red Route status, then the two door buses might start to live up to their potential.
Fundamentally bus services have become less popular as journey time reliability has fallen, reducing stop dwell time will help, better enforcement of bus lanes, bus gates and so forth will also work.

I'm always puzzled by how little Reading Buses trust their customers, the principle of enter via one door and exit via another works well except apparently in Reading where randomly the bus company have decided that its unsafe to open the second door at some random list of stops ... thus any time saving is lost.

Given London uses buses with up to three doors at all stops and in Europe four sets of doors are common I've yet to see any good reason for their "safety" argument.

I'm interested to see how SWR^» (South Western Railway - about) handle my claim which includes a delay on a gWr train. As its on an Annual Season I too wouldn't receive a discount at renewal but I can't claim from gWr as they don't currently have the option it seems so potentially I'll be caught between the two systems and entitled to no recompense for the additional journey time.
I've submitted my January claims so wonder what will come through the post when they get round to considering all the various disruptions.

In good news the Customer Information System seems to have had an update such that it reports the position of First Class in both 5 car sets (Front and Middle or Front and Rear were in use today). The posters could therefore be retired although more specific details about position where Front, Middle and Rear on platforms along the route might still be beneficial.
Also is something not working with the cariage side displays, I've noticed a few which appear blank in service ... perhaps they only activate at low or zero speed?

I guess in theory you could mix and match between Reading to Victoria via Clapham Junction saving on the Tube fares adding in the occasional Calcot to Victoria National Express coach journey (about 90 minutes), I say occassional as the typical fare is higher than the rail fare but from time to time it will presumably be on offer.
Can your employer offer you a season ticket loan to bring the per journey cost down further?

Day 2 of the morning commute Reding to Paddington, thanks to the earlier disruption the 0703 left full and standing (some rather desperate commuters prefering to stand rather than risk the impending 0716).
As other correspondents have reported the station dwell times (GWR^▸ (Great Western Railway) responsibility) the train isn't achieving the booked timings, oddly the effect of that was minimised today as the train had not called as booked in Bath and Chippenham. The train was also consequentially slightly quieter.
Seat reservations seemed to be working on this set.
Sadly nobody could find out which coach was which without entering the train, I even tried asking the first class customer host which carriage she had just exitted, of course having not been briefed to expect the question she didn't know the answer.

At speed in a quiet carriage you become noticeably aware of the wind noise, its not clear if is poor air flow design in the air conditioning or poor aerodynamics of roof mounted components. It appears to be present in both carriages D and E even with air conditioning cut out so time will tell on that one.

Customer Information System on the platforms is still not identifying the carriage order.

Further delays and crew call bells suggest all is still not quite as smooth as it should be.

In good news the seat is more comfortable and less slippery than the old first class seating.
First Class catering turned out and was better than the previous breakfast selection.

Are there sufficient passenger flows to justify running as 2x5 beyond Oxford/Swindon in the Worcester direction, I seem to recall when the Adelante sets operated in 2x5 car one of the two sets was simply out of service until Oxford/Swindon which in turn meant the commuters could be expected to board those in preference to the presumably well laden 5 car set?