That changed with the change of exempt entry going to 60 days. There is now no limit of 2 entries visa exempt via land or sea. The same as by air.
No limit doesn’t mean you can live in Thailand by bouncing endlessly. It just means there is no upper limit, just the discretion of the immigration officer.
Fact: The visa for what ever reason it was issued is valid for 5 years.
Opinion: The immigration officer probably wouldn’t give a monkeys about why it was issued, just that you have it. You’ll have to wait and see if this opinion is valid or not.
You are asking for facts from a visa type that is 3 weeks old. When it’s a hundred and eighty days old people might have some hard facts rather than opinions.
There is no rule that limits UK passport holders to two entries in a calendar year. Whether you are allowed to enter is at the discretion of the immigration officer holding your passport.
To apply for a Non O based on being over 50 in country there is no requirement for seasoning of funds (unless using the Jomtien office). Some offices will insist that the money shows as coming from overseas. Some don’t care where it’s from as long as you have it.
It’s when it’s time to apply for the yearly extension then the funds need to have been seasoned for 2 months prior to application.
In theory that could have happened. Except that in practice it was almost universally accepted that if you were within the allowed 2 entries per year then you’d get away with it. Now it’s too early to see if there will be the same sort of “allowance”.
You can hate it all you like. There was a hard limit of two land/sea border entries in a calendar year. It has changed. Now there is no technical limit.