What are you sceptical about? Unless you use a consulate in the UK and not the Embassy, you have no choice other than to use E visa to apply for any visa in the UK
if you really have a ME non O visa that you got at an Embassy or consulate outside of Thailand, and NOT an extension you bought at an Immigration inside of Thailand, you don't do 90 day reporting as you need to leave the country on or before day 90. You need to stamp out of the country then stamp back in.
You do that every 90 days before the 'Use by' date of the visa.