Turn up ask your neighbours if you really live there, take photos of you in all your rooms and outside of house next to sign with house number on. You will get 30 minutes notice of them coming to check
She MUST use the online application form ,submit the application and pay for the visa. Then she applies for an appointment at VFS Global in Bangkok , pay again for processing and for biometrics, any copies or translations of documents are also charged for if not already done.
There’s a few got visas based on multiple appointments from a Thai dental clinic, these MUST be actual appointments and follow up treatments with dates from the clinic. As for the UK dentist but you haven’t got a chance.