I have spent most of the last 25 years out of the UK and "non-res non-dom".
Not withstanding what others have said this is not rocket science - to qualify you need to (firstly and importantly) make a clean break - no going back for a month after a short time, secondly you need to be away for a complete year (NOT a complete tax year - you need to read ALL of the HMRC bumf) and thirdly you should fill in a form informing HMRC that you have done this. Sorry I can't remember the form number - but it obviously works because having done this last year on departure to Kuwait HMRC helpfully posted a note to my address in Kuwait to remind me to submit my tax return and pay my tax by 31 January - which arrived on 2 February!
Having said all of the above I can't see how this applies to you - unless you are actually earning outwith the UK? Your earnings from property in the UK (like mine) will be subject to tax in the usual way. Anything you earn in the UK no matter where you are located will be subject to tax.
Many people make a big issue out of this and insist that you need to pay an accountant to "handle your affairs" and fill and submit your tax form - not so. We have been filling a return for the last 7 or 8 years with no real problems. Yes it is a hassle and if you are scared of official forms is daunting but for anyone of average intelligence it only takes time and a little effort - the worst thing would be to leave this until the middle of January to start filling the forms - disaster! It was costing us sis or seven hundred a year for the accountant - not worth it, but I dare say someone will do this for less.
I am contemplating the same as you in the near future (1-2 years) so need to have all the financial ducks in a row - but don't intend to rent my house. We have recently started using an agency to rent flats, rather than doing it ourselves - worth it so far, they have a better handle on the market and are no hassle. Suppose it depends on the agent?
All men dream, but not equally.
Those who dream by night, in the dusty recesses of their minds,
wake in the day to find that it was vanity.
But the dreamers of the day are dangerous men,
for they may act their dreams with open eyes, to make it possible.
- T.E. Lawrence -