Am I in the right place?

[WiNgNuTz]

To echo Tom's experience, I also had the diff bearings fail on my 1.4 twice...though I was so good at crashing it into things, that I ended up scrapping it before the second lot completely gave up. Fingers crossed it's something simple for you though, if you've recently had the centre section of exhaust changed, I'd at least give that a quick check before assuming it is the gearbox.