Unfortunately, the nicknames I used are out of date, as they've all been scrapped! Nevertheless...
Any DMU was known as a BUG-CART, though some people called them BOG-CARTS.
Stanier 8Fs were BIG EIGHTS
Princess Royals (e.g. 46201) were known as SEMI's
Class 24's WITHOUT a headcode box above the drivers cab were known as SKINHEADS.
Metropolitan Vickers Co-Bos (e.g. D5701) were known as CHEESEBOXES when based on the Cumbrian Coast line (Workington, Barrow, etc)
Gresley A4 were sometimes called STREAKS
Fowler 5MTs (42701?) were called CRABS, because of the link motion.
Fowler 4Fs were called JINTY's - God knows why