Best online shop for exhausts please...

I need a new back box for my 156 2002 2.0JTS. Its not the same as the TSpark
exhaust system.

The flexi pipe was the blowing part, so they welded a similar sized piece in
and all is well, but there is only luck holding the rear silencer together
at the mo!

Local garage hunted round all over and finally ordered and tried to fit one,
but the bore on (going into the silencer) was completely wrong. Around half
the size of the bore on the car so they (re-assuringly) didn't fit it. If it
can last another month or so, then I can get it done during service. I will
try to get the part myself beforehand.

Cheers,
GT