There's scope for a lot of confusion here and I cannot do more than point out a few oddities.
MV 2734 is indeed a Delage but DVLA records it as 11,959 cc which is far too much for Delage II which was/is 5,107 cc. It's even wrong for the V12 LSR Delage which is normally said to be 10½ litres. The date of registration (1932) does tie in with the account found by Grobmotorix.
Motor Sport has a similar account on pp254-5 of the December 1942 issue but that refers to Noel Gardiner as the man who had that body made for it. I can't say if Noel and Neil Gardiner were different people or a typo - Motor Sport does not refer to Great Auclum but then, apart from one semi-official event, Gardiner's drive hadn't been used for hillclimb events by 1942 so it couldn't be expected.