What steps do I need to take to relinquish my company share and change my visa status to a DTV in Thailand for remote work?

I currently own a share of a business while living and working in the marketing field in Thailand with a non-immigrant B visa and work permit till May 25. I want to relinquish my share of the company, stop my current visa, re-enter on a DTV, and then go full-time remote online marketing for clients back in the UK.

I have a portfolio of work and the 500k in funds available, but the only thing I worry about is my previous month's bank statements, as not much has been happening in my English accounts, and most of my money has been via cash in Thailand. for example, my 500k would be easiest shown if I could place the cash into my current Thai bank account and show it this way. Has anybody had any experience with similar?

Any help will be appreciated.