I did this many years ago (c 2009) , (ie bringing a car i had previously owned in the UK with me when i relocated to work in Thailand). I also know of others who did the same around that time. I have posted about this before on this forum.
my experience was ok and things worked as expected, BUT , i had a well connected person help me out.
I would really really suggest not attempting this in the current environment because;
1) the various duties and the applicable multipliers would mean the all-in cost would be considerable. eg think 300 to 400% over the UK price and ,
2) Most of the loopholes have now been closed and enforcement has been significantly upgraded.
Avoid the stress and buy in Thailand!