Hello, I am Keith, one of the experts on Just Answer, and pleased to be able to help you with your question.
Firstly, when you quit the UK be sure to complete a Form P85 and send it to HMRC. On receipt that Department will classify you as non resident for the tax year after your date of departure and furthermore split the leaving year into two portipons, one resident and the other non resident. Once classified as non resident you may spend up to 91 days in the UK in any one tax year without breaching your non residential status.
Once classified as non resident any income you receive in the UAE is not takable in the UK. It may. of course, be subject to local taxation. Any funds you earn in the UAE may be transferred to the UK without exposing you to UK taxation. The only cautionary warning of which I must advise you is to make sure your UK bank knows the source of the funds if the sums involved are substential to preclude any money laundering inquiries large amounts might attract.
Your mortgage payments are irrelevant in the situation you envisage.
I do hope that I have been able to set you mind at ret on this matter, but do not forget the P85.
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