Exhaust blow has been fixed
gasket between the header and the cat. The mechanic replaced both gaskets to be sure on both sides, and replaced a few corroded U-clamps on the back box. Did the whole thing for £30, cash in hand. Very happy!
Sounds better than it ever did, it must have always had a slight blow.
All that's left to do now is to fix the drivers window regulator that snapped a few days ago, and the car's back to normal. £80 for the regulator unfortunately but it's not the end of the world. Could be worse.