The loco is in lined black livery with a blank tender.
Peter Swift says "The livery of the U class is not that strange for the period – it was repainted into the BR lined Black livery in June 1949 with no crest as they didn’t start to become available until later in the year (Aug/Sep but not I believe until Oct at Ashford). When it received its crest I don’t know but I have a photo of 31799 at Guildford in June 1952 still without one!
The loco was rostered at Reading from January 1949 before moving back to Guildford shed in April 1951. The double reporting number is rather strange. I have seen locos carrying two separate numbers before, but never on the same board and what does the ‘F’ mean? I’m wondering whether it is a military special, perhaps a working off the MSWJR at Ludgershall possibly making its way to Aldershot.
This may explain the use of old ex-LSWR coaching stock. These were still in use during the early 1950s but rarely on regular mainline workings, apart from the peak summer Saturdays when they were short of stock. Pity the set number is indistinct but I believe it may well be set 410 as from the information I have to hand this set comprised of a 56’ corridor Bke Third (SR Dia.2455), with the second vehicle possibly being a 52’ Compo (previously Tri-Compo) (SR Dia.280), whereas the third vehicle I suggest is a 56’ non-corridor Third (ex-Compo) (SR Dia.17). The fourth appears to be lower roof profile or is it just low on its springs".