As a Brit feeling the same frustrations as others on this forum,I thought about returning to the UK for my vaccination.
However at the moment the delta variant is infecting a large number of people in the UK,but most have already been vaccinated.Thus one is entering a country of asymptomatic,infected people,and after 19th July all restrictions on movement and mask wearing will be removed.
The first high risk environment will be long queues at the Heathrow end of the trip,then travel to one's destination by public transport.
For the moment living in one's relative isolation bubble may be the safer option,and await with increasing impatience for a vaccine to become available.
Advice from medical friends in the UK about the Thailand situation was"If it is heading towards the situation in India,get out of Thailand as quickly as possible"