I'm assuming that the O/P registered his residency prior to the end of 2020 when it was a legal requirement to register your residency if staying longer than 90 days. From July 2020 the only residency document available to UK residents staying longer than 90 days was the new TIE. So, although resident, the O/P hasn't yet fulfilled the requirement to become tax resident. I'm also assuming that the O/P's family are not resident and that his economic activity is mainly in the UK.Your problem is that you shouldnt have registered for a TIE. I cant see why you would do that and then carry on paying non-resident taxes. It will look like you are hiding things. You are telling the tax man you dont live in spain and dont have spain as your central place of resident but then you are telling immigration you are a resident. You cant have it both ways and I imagine they will expect you to declare all your worldwide income for the year you received your TIEs. The fact that you have a property and register as non resident means that you could face investigation in the future. If you had no property in spain you might escape them.