Why is it every time I go back to UK I have to apply for a new retirement visa each time because the one I have was issued in Thailand and not UK 

You probably misunderstand the whole retirement visa concept and what you'r saying doesn't make sense, soon UbonJoe will come alone to clear things for you...

Moved to the Thai Visa forum.

Not sure what you have since in reality a retirement visa does not exist.

You can have a non-o or a non-oa or non-ox visa based upon retirement that is issued by a embassy or official consulate.

You can also apply for a one year extension of stay at immigration. If you have an extension of stay you need a re-entry permit to keep it valid if you want to leave and re-enter the country.

 

Probably because you don't have a retirement visa and did not get a Re Entry Permit.

But who knows given the information you provided.

OP, since you state "was issued in Thailand" a guess is that you obtained a non O based on retirement. 

That gives you a 90 day permit to stay in Thailand. In order to stay longer you obtain a 12 month extension. Note your not extending your visa, your extending your 'permission of stay' 

If you wish to exit and return to Thailand you would need to purchase a reentry permit. The reentry permit would be valid till the date of your permission of stay stamp.

However all this is just my guess at what you wish to do as your post is not clear.

Also you start a thread and contribute nothing by way of clarification.

On 6/3/2021 at 11:00 AM, Loon said:

Why is it every time I go back to UK I have to apply for a new retirement visa each time because the one I have was issued in Thailand and not UK 

 

There is, in fact, no requirement for a new non-immigrant visa of the "OA", "OX" or (if you are in receipt of the UK State Pension) "O" variety to be applied for from the Royal Thai Embassy in London solely on the grounds that your previous non-immigrant visa was of the "O" variety which you had obtained through a conversion issued by your local immigration office here in Thailand! Hope that helps.????