The S type diesel has an Achilles heel, whereby the exhaust develops a crack just by the flexi. It can happen on both banks. The Jaguar solution costs £1500, which is to replace the flexi / downpipe wiyh exactly the same component, allowing the same fault to develop some time in the future.
There is a bodge which costs £500, and I'm also aware that a competent Powerflow exhaust fitter can adapt a Powerflow flexi to solve the problem permanently and I understand it costs approximately £60 - £ 80