It is not a requirement to be a resident to be eligible for a Personal Allowance. Last year I re-filed my UK tax and had my UK tax bill reduced to zero on this basis. All may be viewed on GOV.UK in the section Tax On Your UK Income If You Live Abroad. (I’m not allowed to post a URL).
Personal Allowance
You’ll get a Personal Allowance of tax-free UK income each year if either:
- you’re a citizen of a European Economic Area (EEA) country - including British passport-holders
- you’ve worked for the UK government at any time during that tax year
You might also get it if it’s included in the double-taxation agreement between the UK and the country you live in.