Thanks guy, I've just about given up having wasted so much time.
I mean I ask the supplier a simple question "Where can I get the right size replacement fuse" ?
Answer- " Unfortunately even on our web store it is out of stock if you keep on checking on our web site,hope it will be available in the neare future"
Bulls**t, they've never been listed and never will, it's supplied as a unit assembled in China.
I've got a similar 12v adapter for my Canon camera charger (it doesn't fit) but the fuse is the standard larger size glass fuse.
Cant be bothered to waste any more time, suppose I'll lash out $35 and by a new adapter.
Its not really the money, but the principal.

Grrrr