I took my iPad2 in to the apple store on London's Regent St today. I won't talk about the store itself except to say that it was an amazing experience just visiting!
I did a sync (not backup-mistake) before I left home.
The first thing they did was look at the 'behaviour history' which showed nothing unusual except xsyncinfo rebooting a lot. They accepted that this was my own attempt at a fix to the crashing although they did look a bit suspicious of it.
Their advice was to either reload the firmware or to replace the unit completely with a reconditioned ipad2. They are out of stock though so the support tech lady put one on order for me and reloaded the firmware as well. The idea was to see if the firmware replacement did the trick and if not then a new one is already on it's way.
Then just as I picked it up to leave it crashed! So at least it did it in front of them!
Now we're using the original and waiting to see if it keeps crashing. If so then we'll take the replacement. If that one crashes too then you'll be the first to know.
Thanks for all the help so far,