If you were going on holiday to Europe in March

[EnglishRain]

Would Brexit have an impact on when you change currency up, and if so, how?

No, because I just withdraw cash and pay by card when I'm there and get the bank rate with no charges.

I'm not sure how I would get the same rate here as bank/Post Office/travel exchange rate is a few percent poorer, so I'm ahead even if the exchange rate is against me.

Also, for all the ups and downs over Brexit over the last (nearly) 4 years, the exchange rate spread has been about 10% from best to worst, so based on me spending a few hundred euros on food, drinks and activities, it'll matter to about 30 quid at most, and within the £1k+ cost of our average week's holiday, I CBA worrying about it further.