Have rounded an allen bolt off with my cack-handedness, not enough room to get mole grips on to undo, what are my options?

What / where is the bolt?
Drill it out
hacksaw a slot in the head of the bolt and use a screwdriver.
Use a screw extractor
etc

Old flat blade screwdriver, hammer hard, undo.

Or get the drill out.

Bolt is the pinch bolt on the drive side pivot bearing on an orange 5 🙁

Wack a star bit (torx) into it – Worked for me – choose a sl. larger one and hammer it in – Done it loads of times and works a treat on rounded hex's – just chuck it away after and get a new one 🙂

Drill carefully then 😉

Bang in a wrong size allen bolt / bit (imperials are generally available that are a bit off metric), or a Torx bit that's too large, as the bolt head has some room to deform.

You will want a 4lb hammer.

Try some freeze'n'release and a kettle full of hot water too.

easy out bit or like above

use a dremel to cut a slot and use a screwdriver to remove.

listen to the man who said knock a Torx bit in

Get some easyouts, they are reverse threaded and tapered, come in 5 sizes.
Halfrouds usually sell them.

I'd really not bother with an easy out, except as a last resort. If it stuffs up and breaks, you've got a nice lump of almost undrillable tool steel attached to the bolt you want to drill out.

The torx bit method has never let me down on seized up old brake caliper bolts on cars, for what it's worth.

whatever you use, once you've hammered it in there, try not to wobble it about too much. try and keep pushing it in to the screw head as you attempt to turn it. ideal if you have a driver, can lean on that, then grip the shaft with a pair of pipe grips or something and turn. once it's loosened off you're good.
also – bin the allen key you rounded it out with and buy a new one. otherwise you'll just do it again probably.