Thanks for info.
I just done a cost comparison (METV v Elite), and calculated the extra cost of Elite over a 5 year period would be around £5k (212k baht). However, this does not factor:
1. Hassle reduction
2. Additional cost of flights home (2 or 3 during 5 year period)
3. Potential issues regarding having a ton of METV stamps (should I continue with METV)
4. The additional freedom to travel to nearby countries on dates that suit me - and more importantly without fear of immigration questioning me (assuming that's not a thing with Elite)
5. Potential changes in exchange rates due to the £ being so * currently
All in all, it seems a very close decision! Probably a couple other factors I've not considered - yet