Ooooops sorry to hear that Alun, it can and does happen to the best of us
The company you need are propeller solutions http://www.propellersolutions.co.uk
Talk to Tom on 01258 858784
I once had a piece of my skeg go missing on my previous outboard (150hp optimax). Tom then worked for propeller revolutions and did a first class job of welding it up so I guess he would be able to do the same for you.
Martin