Thank you for all the contributors to my post, you have all been very helpful.
I clearly understand now that I must apply for the non-O immigrant visa outside of Thailand and then re-enter Thailand on the 90 day visa and open the Thai bank account, then deposit the 800,000 Thai baht, then wait for approx 2 months and apply for the extension for upto 12 months on the non-O visa.....then renew the visa every 12 months and attend immigration every 90 days for reporting.
What is your best advice, I don't mind paying for professional service from a visa agent in Bangkok, do you think I would be eligible for a retirement visa and of course the Thai bank account if applying from inside Thailand, I am living with my girlfriend in Sakon Nakhon Provence and she can confirm that I am residing in her family house.