@Ja***
If I was a betting man I'd say you have a slim to none chance of getting anything more than a 90 day single entry Non-B visa IF that from any thai consulate in a near-by country.
The days are long gone when you could pull those year-long, multi-entry Non-B visas (which require you to exit/re-enter the country every 90 days) just for the purpose of "looking a business opportunities" here.
Good Luck,
I would also say you should make your own topic asking your questions because it's not really related to getting a year-long, multi-entry Non-B from the thai consulate in London