Hi James it can be done,my wife changed her name last year to meet the requirements of getting her Uk passport renewed.
Its an expensive and time consuming exercise though(search for relevant threads) and I would imagine it would be easier to do in Thailand.
Briefly summarised your wife will have to give Power of Attorney (POA) to someone in Thailand to do some of the donkey work in getting the relevant documents to the correct people.Lots of tooing and frowing postal wise ; and the Thai Embassy in London 'need' to see the original house registration book(with the new name change).
Best bet is to get your wife to contact the Thai Embassy via facebook.They will tell her what's required.
Good Luck...it is doable.
ps was going to post a link with my thread on from last year but all my posts have disappeared from last year!