Can I renew my retirement visa from the UK during Covid-19 restrictions?

Same situation for me ... 20 october 2020 .. full process to start again and double work with COE ... can not sleep sometimes

Nope, you can't get a new yearly extension outside the country SO if you can't get back by the time this one runs out, it's done..

You would have to WAIT until retirees are allowed to request entry to thailand (because at this time they are not).

Then you would have to start the whole process over again to get a non-O or non-O-A visa from the thai consulate in the UK before you would be allowed to enter the country

AND

You would have to meet any of the entry requirements they have in place at that time.