For us it was basically a series of pictures of us over the last couple of years. And you could see from my weight gain that there was some time between the first and the last 😂😂
Girlfriends finally woke up so I can double check what I said previously;
When we applied for her visa to the UK, she had only 15k THB in her bank account, and she got the visa. What I think was most important was detailing in the sponsor letter exactly how much we expected to sponsor her for, even estimating how much money a day would be given to her for her expenditure, and of course the sponsor bank statements. As well as adequate evidence of relationship.
I dont think your girlfriend needs 500k in the bank. It might help, but she doesn't need it.
Contrary to what others have said here, my girlfriend came with me to the UK a few months ago we didn't need to put any amount into her bank account.
The most important IMO was the UK sponsor bank account, and in the letter detailing how much money per day she is expected to spend and that the UK sponsor is happy to cover those costs, as well as sufficient evidence of relationship.
Perhaps we got lucky, but she doesn't even have a job "on paper". We just provided all the evidence required as well as any additional evidence we thought necessary.
I'll ask her what I may have forgot when she wakes up.