Just to let you all know I've sealed the case back on the PO and have completed my first ever proper bit of watch repair work!
I'm mightly relieved I can tell you!
The hardest and most tricky part I found was removing the stem from the old crown as I had to 'gan canny' with two pliars - eek!
The old crown tube was easy enough to remove with a pair of fine needle nose pliars, with a twist to break the loctite or what ever sealant was used, it then pulled right out, mind you the qulaity of steel used was awful.
The new crown screwed down nicely on the stem and the new tube was popped into the case and I used UniBond metal repair which seems to have done the trick.
What I've learnt is that with some basic tools a lot of research (this place has been fantastic for this) and a bit of guts a 'relatively' straight forward job like this is achieveable even by a short sighted clutz like me!
It also increased my admiration even more for The Zigmeister with his incredible skills on the more high-end jobs.
I'm off for a calming pint now, cheers!