Well . ............. she has a visa from some time ago giving her 2 years Residence . In her old name ( original name ) .
Then later an ILR visa in her new married name . A stamp from Thailand saying her surname has been changed . And then much later .... in 2015 ..... a brand new Thai Passport back in her old name .
She has sodded about so much that she deserves to have problems . She asks for advice --- and no matter what you say .... it doesn't matter AT ALL what you say .... she says " No " -- because someone else has said something different .
My final advice was " SHUT UP ! Don't you say another word . Not one . Now apply using whatever name you want and have lots of documents and copies ready showing that you have 2 names but the current name in your current Thai passport is the name that you want in your UK passport . And I hope you don't get one ."
She clearly wanted to say " No " --- but she didn't .
Thank you for your thoughts.