Just thought I would pass on the benefit of my experience over the last couple of weeks; hopefully some people might find it useful.
My weekend / hobby / backup vehicle is a 93 Isuzu Trooper, 3.2V6 SWB. After the last MOT, one of the advisories was a minor leak on the exhaust, which on inspection turned out to be in a flexible coupling. The flex coupling sits in a wishbone shaped piece of pipe, which joins the two downpipes from the engine banks into a single pipe.
Anyway, the leak has got slowly worse and my need for the car has got greater (change of job and company vehicle returned) so I decided to do something about it.
My normal exhaust supplier said they couldn't get hold of the wishbone section of the exhaust, and that apart from the rearmost exhaust sections the Trooper exhausts are a dealer only part. Which sounded potentially painful in the wallet area.
The second place I spoke said they could get hold of the part, but it was 200 quid. There was also a risk that, because in the past someone has tack welded the wishbone section of the exhaust onto the cat, I might need a new cat too - which would be another 300 quid or so. Eeek.
My third call was to a place in Leek, Staffordshire (All Car Exhausts, shameless promotion for them but I promise I am independent and just recommending them because I'm chuffed with the outcome). I told them the problem, and the guy on the other end of the phone did acknowledge that the wishbone section on the exhaust would be "strong money", even without the risk of having to replace the cat.
Just as I was thinking it was time to bite the bullet, he went on to say "But if you bring it in, we can cut the old coupling out and weld another one in its place. No need to worry about going anywhere near the cat."
So, to wind up a long tale, 60 quid for a job well done and a nice sounding vehicle again, rather than at least 200 and potentially 500.
If anyone else finds themselves in the same situation (and like me, isn't able to do the repair yourself) then I recommend doing a bit of phoning around and asking the question.