The 1712 and 1812 are slightly odd services - anyone with sense would use the 1706 and 1806...
I disagree - Not odd but rather quite refreshingly different. A peak time train where you can get a seat at the last minute and have space to your side. Added bonus for Twyford passengers that it arrives on platform 4. With time on my hands 18.06 is great but need to be there early!
Yes, the 18.12 takes a bit longer and it would be lovely if it could use the main line to Slough but let's not shout too loudly in case
FGW▸ will see it as a loss maker if its not "standing room only".
The 19.06 (3 car) is usually a bit of a scrum to get on as it usually arrives at Pad about 19.02 and is packed to the rafters. (interestingly the departure boards usually say "preparing" when the train is still 5 minutes away)