Don't worry lads. As soon as it happened I documented everything, all communications, and went to small claims court. Got a CCJ for the full amount, had it kicked up to the high court, got a high court writ, and there are now bailiffs going after him for the money.
Work must go on in the mean time though naturally. Believe me that £9k hurt, but the flip side is being grateful it was only that £9k and I didn't give him the whole £28k.
I think I speak for myself and others when I say keep us updated on this. It'll be interesting as a lot of small traders actually forget to do the whole LTD thing and register as sole trader. As a sole trader there's no legal distinction between personal and business assets, meaning anything they own is up for grabs when the bailiffs come knocking