Don't do it.. they change once they meet other Thai girls who have been in UK longer and they want what they have and what their partners give them but don't realise it takes time to have those things.
Residency takes a long time and she will need to pass an English test now.
Her initial visa will be 6 months.. if she gets one.
U will need all info , emails , messenger chats , money sent to her via banking or WU. Also photos of U both , U with family.
But most of all , a reason to return.. a baby , or business here.
And she will need money in her bank.
It's more on her return , rather then on Ur financial status , although obv that counts.