I'm looking to replace all discs and pads at the weekend and wanted to check the size of the bolts used for securing the discs so that I can buy some nice new ones before taking things apart.

I found good info on tools needed here:
can't post link
but can't find the actual size of the required bolts anywhere.

Can anyone help me out, please?

ETA - I DID find useful info on tools, but I'm not allowed to post the link. It was thread title: 100hp disc change help

Still can't find the bolts though...

There's no point in replacing the disc retaining bolts. The main problem you might have with them is that they can seize in place and, being made of very soft metal, shear off with minimal force. The best approach is to apply very low torque to them in order to remove and if they won't shift then apply heat.
Even if they are difficult to remove, if undamaged they can be cleaned up and re-used, since they don't actually hold the disc in place in normal driving conditions, just keep it in place when the wheel is removed. If they shear off then it's not worth trying to extract the remains from the hub, best just to re-assemble without the bolts.

Excellent advice. Thanks very much for the speedy response. Much appreciated.

By the way, if you really want to replace them, since they have an elongated, conical head, designed to hang the wheel onto whilst you insert the wheel bolts, you will only find them at a Fiat dealers or, of course, a scrapyard (they are common to many small Fiats).

Thanks again. Driver's side was fine but both locating pins on passenger side sheared off. Luckily, they didn't leave any stubs protruding or anything. Refitted wheels no problem, though, and everything is hunky dory.