Hi. My name is*****'m looking at your question now and will post my answer or ask for more information here in a short while.
Assuming you have been non-UK resident for tax purposes from August 2012 until 5 April 2016, thr earnings for those years won't be taxable in the UK. You should get split year treatment for 2016/17 but only if you are UK tax resident in 2016/17 and 2017/18. Take a look at the notes in section 5 here and at the flowcharts here and here. Split year treatment means that your overseas earning from 6 April 2016 to the date of your return to the UK won't be taxed in the UK. Assuming you stay in the UK, you will need to meet the criteria under one or more of Cases 4 to 8 in section 5 of RDR3.
If you go abroad again, it complicates matters and you would need to ensure that you don't breach the limit to the number of days you spend in the UK in 2016/17.
I hope this helps but let em know if you have any further questions.
Hi.I'm just following up to find out if my answer helped or if you have any further questions.