@Graeme ******
what about getting your passport to the thai consulate in the UK to get that year long visa by sending it to someone in the UK who could send it on to the consulate, have them send it back to them and they mail it to you to use when you come back in?
Just spitballing here, because I know people who used to routinely go to the Philippines send their passports to family in the UK, get them to forward it to the Thai consulate in London, get the visas stuck in and sent back to the UK people and then back to the holder of the passport in the Philippines. The ONLY rule when buying a visa for thailand from a consulate is you can't be IN thailand when you buy it and the address has to be in that country where you apply.
You might wanna consider trying it. You apply online anyway for the visa, all they can do is deny you and you're out nothing by trying it.