Thanks for the words of wisdom! 8)
Some more bits of progress:
The steering column is virtually where I want it now, but I need to mount the seat, put the pedals back in, and mount the gearstick in order to finalise the position. I've moved the steering wheel to the passenger side slightly to give my accelerator leg some more room…
I've also prepped the rear to accept an ali sheet as the rear bulkhead. There's plenty more holes to fill up with fibreglass and weld though…
The other side is now stitch welded too, although some parts I have seamed on, like the anti-roll bar mountings..