Hi Stephen
I was using BTL as an investment vehicle for some 8 years (when there was good capital growth). Looking over your figures there will be probably little or no income to worry about taxation with the figures you have given here.
The void periods, maintenance, gas & electric safety checks, etc etc will most likely eat up anything left after the letting agent has had his share. Then as an Expat you have to think about how much you are being charged for repairs unless you have plumbers and a general handyman you can trust.
My excuse for selling up my equities and going into BTL was that I thought stock indices were looking toppy and house prices were beginning to climb. It was a good call but even then there was not much rental income profit to be had due to higher interest rates. It was Capital growth that paid off and IMO I seriously cannot see much of that for the rest of this decade, maybe around couple of percent a year in line with general inflation. But that is only my opinion, being right before obviously doesn't mean it is going to be right this time so the choice is down to you at the end of the day.
As regards Investment Trusts, they are some fairly low cost ones out there but if investing for longer term try to spread your money about, maybe a mixture of income, growth, generalist trusts could be suitable. Since end of 2008 I have been making regular contributions into a UK Income and also a Generalist trust (spreads money into different gegraphical regions). I feel happier with doing that than being an Expat LL and can sleep better at night.
Expat LL's will have rental income taxed in the same way as a UK resident LL. Rental income minus Mortgage Interest, Letting Agent Fees, safety certs, repair expenses will be taxed by HMRC as it is UK Income. UK Citizens continue to have a tax-free personal allowance. One other thing to beware of is the country you now reside in and how they treat income and capital gains (when you sell rental property) from other countries. So you need to check on the Double Tax Treaty (if one exists between UK and your host country) on HMRC site
A lot to think about so don't rush in to making a decision on something major like this. Best of luck with whichever route you take