Well thank F for that....
Stripped my car apart this evening, first attempt I've had at looking into what the issue was from the weekend. Turns out it was simply a badly bent left rear hinge pin. Not sure when I would have bent that, but I'm guessing it would have been during the last meeting, although don't recall hitting anything hard enough to bend it. Do remember hitting the wall at the last Carpet wars round, and I didn't check the car between thoose runs... so that possibly where the issue started.
Still, given me a good excuse to strip the car and give it a fettle, even re-built the diff (although it didn't need it, even after 50+ runs
), only thing I didn't rebuild were the shocks, but I'll proably do that some point this week.
Hopefully I'll get a run next weekend, otherwise it's going to be a few months before I get the next opportunity to do so, as my other hobby kicks off it's season soon. Hey ho, have to see what happens.