Thanks.
I had anticipated the duplicate keys issue.
As I have part of the ignition lock missing maybe this is the answer?
https://www.ebay.co.uk/itm/403939615...3ABFBMsPfm47hh
I know there will still be the seat lock but I don't lift that often.
I've had some pics of the welded tank (can't post due to tech incompetence) but it looks OK. Just waiting for my mate to let me know what he's going to do about re-painting the areas around the welds but it doesn't look too badly affected.
Looks as though I shall be able to get the bike back on the road for Spring now fingers crossed.
I'm told after the work on the engine and clutch it runs quietly and very well now.