Hi Guys,
So I went and registered the trailer using 'ADI1511' as the chassis number.
The Lady at the counter said because it was ex Army I wouldn't have proof of origin as it had never been registered, which would mean I would have to jump through all sorts of hoops and inspections, to which I said "actually, I do have proof of origin, this is my Grays Auction receipt and they are the company that directly sells off the Army equipment, so, proof of origin"
She then went off to talk to a supervisor who said it was fine to register as a 'category 4, pre 1988' trailer and they wouldn't need to inspect it.
She then put it in the system as Brand 'ADI' model 'ATM up to 1.02T'. I then politely asked if the model could be changed to 'No 5' as there are about 3 others registered like that. She said they are meant to put it as 'ATM up to 1.02T' as it is a light trailer, but after about 5 minutes of her searching the database and not finding it (and me telling her how to spell 'No 5'

) she said "oh, we do have that listed.." and she changed it for me.
So now it is correctly entered as 'ADI' and 'No 5' as model, '1966' as year
Only thing I was told I would have to do is also stamp 'ATM 750kg' on the trailer somewhere (I actually haven't stamped chassis number or anything yet)
I used 1600kg for axle rating and 2500kg for tow ball coupling rating. Hopefully all this is of some help to others in the future.
Thanks for everyone's input, much appreciated. Now I just need to source spare wheel, canopy bow and canopy
