If £20,000 is a pittance to you, then I am happy for your success. But I would rather import THB 65k per month to spend as I want/need.
Interest on that money would be say 5% = £1000, about Bht 40,000 per year. Not life changing money.
COL is cheaper in Thailand? Small Singha is Bht 38 here, same as in UK.