RE booking early and ETAP, looks like they've changed their policy on payment, just checked my account and it's down £261 from their pending transaction. In checking on booking.com they now state they'll take the money 'anytime after you book'. @Noodle you may want to check that out as well.
It's slightly forced my hand however in terms of committing to the event, so... anyone wanting to share?
edit upon further checks, the cancellation fee is also the entire booking cost... I.e. £261 for myself... So it's now, not slightly forced my hand, but pretty much fucked me if I don't go... So you definitely want to look at this @Noodle man.