Having thrown my toys out the pram, I walked round and picked them all up again. I'm now doing 1:43.5s (usually) and actually won a race yesterday by 50 seconds (even though there were two people who had a lap time 1 second faster, but they hit each other after the second corner).
Now I just need to aim for 1:42s... Is anyone still playing this, fancy setting a new time trial?