Thanks for all your help - this is such a friendly forum!
I've been told that you can't weld a repair when it is near the flange - any truth in this? Having spoken to the mechanic again, I've found out that it is the central part of the exhaust where it meets the rear section that has corroded and basically come apart. Hence I need a new central section.
I got a quote from Z centre for the OEM part for £175 + VAT, so a bit cheaper than the Nissan Dealer.
My only concern is that if one part of the exhaust has rusted enough to give way, how long before the rest or is this the most common place on the exhausts system for it to fail... I'll have a think about the Scorpion system - does it make the sound much louder? As I have a soft top I don't want to drown out the music!
Jeff - I'll PM you about that place in Lincoln.
Thanks for all the help!