It really is mysterious. As long as clutch pedal is depressed it can shift through the neutral position (or any other) without grinding. So to start or have engine running need to have clutch pedal in. Then can drive in 2nd or reverse (in all of it's many positions...). Have only done this to test rest of car's operation.
Thought it may have been something obviously wrong to someone, but it's just weird!
Will start looking for another trans to have installed. I'm sure there are parts missing or out of place in this one.
Thanks for replies, at least I know it's just a strange situation!
Don