Excellent machine! For (some) cab panels, try Brian Whiteside (nr Poole) (Wimbourne). He has some other stuff too. Rhys Hughes (Fishguard) also has loads of RL stuff. Are the panels beyond repair??
It is fantastic to see one the of rare ex-AFS wreckers still in existence, and your photos show clearly some of the interesting mods at the rear end.
There is a really nice guy out there (Tony) who has lovingly created a beauty of an AFS wrecker from the "standard" army version, with these AFS mods. In recent years he has taken it to the Welland Steam Rally as part of an AFS event, but unfortunately that won't be repeated this year. You may well know him...
I am the current custodian of two ex REME wreckers which I am absolutely mad on. At end of May, REME are arriving as near to my home as they can get with a MAN SVR + trailer to "borrow" YSU 350 for a ReccyMech get-together and action day with some other, BIG, ex REME wreckers, including Scammell and Foden EKA. YSU 350 still needs some work on the cab, but wiring, air, and brakes are all renewed. Still work to do on it. The other I haven't yet touched, but it drove 100 miles OK before it overheated. (Turns out the engine block cooling is blocked up.)
I have an original copy of the User Handbook which I am going to get copied and when it is done, if you want, you are welcome to a copy.
Regards, Dan