Hi Will,
I'd be surprised if it was the crank position sensor, as if these play up the car doesn't usually start at all.
The relays for the fuel pump, ignition, and starter are all within the relay module, which is a black box attached to the bulkhead about the size of a packet of fags. If you need to replace this, they're readily available either secondhand on ebay or new, as they're the same as fitted to MGF's (Part No YWB100970).
Before you go replacing the ECU, have your original one tested. When my 1999 +4 was playing up (sometimes it would start, other times it wouldn't - it turned out to be the starter motor in the end) I took mine to ECU Testing Ltd in Heanor, Derbys. (
www.ecutesting.com). They put them through all sorts of tests for about £55.
Hope you get it sorted.
