Thanks for the advice guys - here's what's happened today.
Got some pictures of the hole:
That's a 30cm ruler.
Spoke to my local councillor, and he told me that he's been campaigning for over a year to get that road re-surfaced, and will send me all his correspondence to back up my claim... so that side of things is looking good.
My mate and I looked over the bike today, and it appears as though the head barings have collapsed, but obviously, I'm going to take the bike in to be looked at thoroughly to see if there's any other hidden damage.
Touch wood, it's all easily repairable and will be paid for.
In response to various comments:
I only took my gloves off for a low speed run round my block so I could feel if there were any problems - when I rode home originally I was obviously wearing my gloves and didn't feel anything, so it was probably a good job I did what I did on the second run.
I'll be sending a mail to MCN shortly
And finally, what is B.A.S.A.T.?
Cheers, Matt.