I used transfwise three days ago to transfer money from UK to my Bangkok bank account to ensure my account remains open. Money in account in 2 days and great rate !
I think she will find getting a UK visa very difficult. I am in the UK and my wife can not get back to Thailand. She has her name down for repatriation flight. I dont believe the UK gov will let people fly in with no way out. UK visa are not the easiest in normal times !