Well done Reg, hard luck LM,
It is the BAe P.1234-3. Not a very inspiring set of numbers and one gets the impression that their hearts weren't really in it. NATO was keen but BAe just let it drop!
RegDep has control 
OK Nigger, time for walkies!! (it IS a black Lab really it is!)
Edited to say I need help here, when I went to post, LM's post just had the correct acronym but Reg had posted with that and the project number and a mention of LM's post that I thought meant that he had found it without that help.