Who knew? Anyway, this is what I've been working on.
I've decided against making up a gearbox mount for my beefier TR/saloon gearbox to bolt onto the existing Spitfire gearbox mounts as I'm slightly suspicious as to the strength of the bolts holding the overdrive unit in place.
Instead, I've made up a bracket that'll bolt onto the existing mount point on the gearbox. This will mean having to cut the body shell back a little, but I'd need to do some anyway to get the overdrive unit to clear.
Initially, I planned to use the mounts I'd made for the previous location, but I remembered I had a TR6 mount I had ordered a while back and thought that they would be a lot better suited than my ones.
This is it all mocked up in place:
Next up is making some little brackets to weld onto the chassis with some captive nuts to bolt the whole shebang in place :)