Problem solved now.
Brought home 2 Ford Blitz trucks yesterday from a farm about an hour away.
So now I have 2 gearboxes to play with as well as another flathead V8. I now also have an overflow tank too.
The more complete truck had both windows fitted in their frames before we left the farm. By the time we got to my place one had slipped out and dropped onto the tray of the tilt truck. Amazingly it didn't break!
Plushy, thank you for your offer but now I will not need to grab a gearbox off you.