Any question answered...

I'm the office now anyway, so the builders will just have to deal with their lack of reward biscuits.

The problem is not lack of leverage - it's inability to stop the crank from rotating with the cheater or wrench. As I understand it, anyhoo.

Yes, this. Though if I were to get the pedal off I could use the hoover extension method to have leverage over both which theoretically might make it easier to keep the non-DS crank in place. Your idea of putting some wheels on is good, though - I've even got a low wall in my front yard that might be able to keep the whole thing perpendicular to the ground and so even better than a curb. I'll give that a go.

If you need a hand later I should be free. Just send a PM.

Thank you! I've got a hideous virus at the mo so I might be utterly wiped out from it this evening but if I'm not on death's own doorstep I might take you up on this.

Take the chainring off, rest the BB on a bit of 2x4 (liberated from the builders), that'll raise the BB high enough that the spider arms won't hit the floor but the cranks will.

Apply LEVERAGE

The chainring doesn't come off without the crank being removed. Srs. Hasn't got a spider. It's some weird thing I've never seen before that presumably uses strong magnets to stay assembled.

Thanks all, I'm sure I'll be able to provide you with a thrilling update soon.

Vis-a-vis cars, Zipcar is probably your best bet, Howard.