Interestingly my car ( # 1646 ) was also supplied by University Motors, Balham, on 28 September 1974 ( this branch dealt with Personal Export Delivery ( PED ) MG B,MG BGT and MG BGT V8 within the UMG ) and was a PED car.
The Service book for my car is a PED version which differs from the standard Passport to Service in so far as it has a dark blue cover with no MG notation ( non marque specific ) on the front as it covers Austin - Morris - MG, Jaguar - Daimler, Triumph, Rover cars, Range Rover - Land Rover.
In addition Personal Export Delivery is over printed in Pink throughout this publication.
Firstly you will need to source the MG version of the British Leyland Passport to Service ( Pub No : AKD 7749 ) there are several editions of this.
Originals do turn up on Ebay reasonably often and I recently sold an unused Original copy on there in order to raise some much needed funds!
As Dugald rightly states they were enclosed in a plastic wallet. The easiest way to get one if missing, is to buy a used Passport to Service for the Austin or Morris Marques off eBay which are relatively cheap.
You also require the Austin Morris MG Wolseley Owner dealer directory. This will be the narrower edition mirroring the size of the passport to service booklet.
There would have been the following card inserts :
1) British Leyland 1000 mile service voucher ( Pub No: AKD 7901)
2) MG owners Service statement ( Pub No: AKD 7750 )
3) British Leyland Warranty Conditions ( Pub No: AKD....) I do not know the full reference for this but The Personal Export version is AKD 8063.
Unfortunately I do not have any original UMG paperwork either, other than the above mentioned Passport to Service and I would be very interested in anything passed onto you by other V8 Register members. I would also like to source the appropriate era original UMG rear window decal, I have a reproduction one which I do not believe is an accurate copy of the original both in format and size.
I hope this limited information is of some use to you?