Slightly smug post warning, the day it was announced BJ was going to be PM, I bought all our holiday money, I got €30 more than I would have the day after, so I’m so what of an authority on this sort of stuff*
Personally, I’d wait. ‘No deal’ seems, at least on the balance of probability, less likely than an extension at this point. A deal being a very distant 3rd – wait a week for this to be confirmed and you might earn that extra beer.
As for waiting any longer, well, if you lose the gamble and we go no-deal you’ll have bigger fish to fry – assume you’ve bought insurance?
A VONC seems, again on balance more likely than a GE at this point, but this is far less certain, if we do see a Caretaker government, Westminster will swing closer to the EU and closer to a chance of remaining or going for a very ‘soft brexit’ if this happens we should edge closer to the €1.3 = £1 Norm.
In fact given some cynics are saying the EU is facing a recession and we probably wouldn’t, you might see a higher peak, but I doubt it would materialise before your holiday.
*I am, in no way an authority on this sort of stuff.