Thank you very much for these reports: they are helpful. Taking them one by one:
I'm not sure if this has been posted, but the 1975+ blue 4 COR/RES/BUF rear driving unit stays green.
Found and fixed.
The LNER Tyneside Parcels EMU has an expiration date of March 3162...
Found and fixed.
...and does not change to the green livery, while the normal version does.
The green livery for this does not appear to have been drawn by Junna, who created these. I am not sure whether this was deliberate or not. Does anyone know whether the Tyneside MPV actually ever appeared in the green livery?
The second car of the 312 is in all-over blue, while the rest is blue-grey
I can't reproduce this, I'm afraid: it may have been fixed since the last release.
The 4 SUB or class 502 does not go into blue, even though I am lead to believe that they did.
The process of producing graphics for the various vehicles in all of the liveries in which they appeared is not yet complete, and these are some of the vehicles that do not yet have multiple liveries.
Also, I cannot use the class 486, it shows up with a pink bar. Not sure what that means.
Pink means that the vehicles are available only as upgrades. The 485 should be an upgrade to the 1938 stock, but the upgrading was not correctly specified. Now found and fixed: thank you.
EDIT: What year is best to find Jaffa Cake, as I have only seen it on the MLV.
I do not think that this livery has had many vehicles produced in it so far: it was a livery of the early 1980s (available in this pakset from March 1985 to June 1986).
Thank you again for your reports. These have been fixed in the sources on Github, and will be available in the next release. It may be some time before the next release is ready, however, as I have not had much time to work on Simutrans as late as I am still in the process of moving house.