The stubborn stud sheered off flush with the manifold. Luckily I was working at the local garage and had access to all the tolls need to drill out the remains.
Amazing how different it is having air tools, sharp drill bits and experienced mechanics on hand.
Decided to drill out and use a nut and bolt instead of a new stud. Needed to grind the top of the manifold flat to accept the nut - All took about half an hour and the new down-pipe is a last fitted along with copious amounts of copper slip.
Now need to sort out where the power steering pump is leaking fluid from. I've had this 90 for about six years now and there is ALWAYS something that needs sorting!!!
Time for beer now....
Regards
RichardB