Tax is a personal responsibility, but as an EU resident (not going to say where), I pay my tax in Portugal at the non-resident rate = 25%
if you are resident in the UK, you pay your tax there. If you are resident in Portugal, you pay tax at the resident rate.
Many answers to your questions are here:
Netjets Europe Conditions, but as I said, tax is a personal issue and you should take professional advice as I only know these three cases.
MOG