do i need to have money in thai bank for a 90 day visa

Hi everone, we have a house in hua hin and normally just come on a 30 day visa then extend for 30 days. we are hoping to come for 4 months,. whats the best way to do this without going out of the country too much? I was hoping to get a 90 day visa and extend but ive just tried to apply and its asking to show 800000 b in the bank. We have this in uk but not thailand.

Would we be better getting a 60 day visa then extending for 30 then going out of the country?

Any information would be gratefully received.