Why Udon Thani and have you met this 'Friend' in person before, there are many visa options, if you are over 50 then a retirement visa would probably be the easy way if you meet the requirements. opening bank accounts is no longer easy so maybe use the services of an agent.
Just one Question, Why would you even be thinking of taking someone you hardly know to go and live in the UK , Have you tried living in Thailand for a while first, what makes you think she will even like the UK which increasingly is becoming a dump.