Austin Healey 3000,,,same setup but I got the button on the dash. You can "jump out" the switch on the trans to get OD in 1st or 2nd, but trans
oil pressure will be low and the "cone clutch" OD might slip and burn under heavy throttle. 8 gears, lol.
MGC,,,I always wanted one of those! Very hard to find! Had a bunch of MG(A's, B's, GT's).
The OD unit was a "Leycock De Haviland", I believe, and was used everywhere you want to be in European circles.
Ernie