I recognise that set of numbers (though I'm less convinced by 5795). But what about 5301 to 5356?
Yes - those look like a series I missed out. As I recall 5780 to 5795 were the ex Newcastle 2 car units with the larger newspaper and luggage vans than the 5701 to 5780 series. So depending on when you were around there, the 5795 number could be out of place for you.
EDIT TO ADD▸ - from various Wikipedia pages:
In the earlier, Southern-style 5001-5053, 5101-5260 series, most units (all of which were one class only) comprised a driving motor open saloon including brake at each end of the set. sandwiching a trailer open and a high-density (6 per side) trailer ten-compartment vehicle with access from the passenger doors; there was no gangway down the coach.
The production vehicles in the BR▸ series 5301-5370 had slightly higher capacity motor coaches, identical vehicles at each end of the set, with an internal partition splitting the saloon into two smaller ones, and a pair of identical trailers each comprising 5 compartments and a 5-bay open saloon, with the compartment end of each coach always back-to-back with its neighbour.
When the South Tyneside line was de-electrified in January 1963, all but one of the 1951 EPB stock was transferred to the Southern Region
Class 416/2 Standard BR MK▸ 1-TYPE stock, 5701-5779 (subsequently renumbered 6202 - 6279 from 1983), and the former Tyneside units, 5781 - 5795
So ... there was no 5780. 5261 and 5262 were mixed Southern and BR series units, made up from vehicles left over after collision writeoff from other units. (5005, 5008 and 5009 also varied from standard)
