Oscar D as far as I know, Austers that had wing tanks didn't have an aft of firewall fuselage tank. This would make fitting instruments a lot easier. It also means that you can change the upper engine mounting bolts without removing the fuel tank
I think the wing tanks were either 12 or 16 Imp gallons depending on model.
I've seen the ad for the Gipsy Major 1 on PF. I think they were the 130hp version, the Major 2 being 145hp. Any comments on this chaps and chapesses?