I assume even with the unforeseen 103 quid extra you're still going to be coming out on top with regards to the cost of your trip by going ex-EU rather than ex-UK?
If you're doing ex-EU with all the extra potential for things to go wrong just to save 100 quid, then duh. I'd just be glad you managed to get off relatively lightly this time.
I have done this to save even less than that just to stick 2 fingers to the UK governments' APD.