Anyway, a poorly performing endowment matured last year and instead of using it to pay-off a bit of the Mortgage we are using it to part fund a new 4 seat Plus 4.
This is exactly what you should be doing!
As Peter has said, modern Morgan's don't really require any mechanical/engineering knowledge, but there definitely tips and tricks about other things that you'll find on here.
Keep us posted on your new motor - you'll have a lot of fun.