Posted: Fri Oct 15, 2021 11:50am
Just a word about taxation......
You cannot elect to be tax resident in both countries. If you become a resident of Spain via NLV and TIE you become tax resident after 183 days.
You need to register with the Agencia Tributaria by submitting a Modelo 100. This is whether your income reaches a tax threshold or not.
When your tax return falls due you should file one. That return should include all your income regardless of country it is earned in.
The Tributaria will send you a Certificate to confirm you are in the Spanish tax system and you should send this certificate along with the HMRC Double Taxation form (DT- individual) to the HMRC to exit the UK taxation system.
In my view it would be very unwise to try to remain permanently in 2 tax systems especially if it could be considered that someone was declaring income in each of those systems below taxation thresholds in order to reduce or avoid tax.
Steve