you can sell in the uk no probs. Just watch out how long you plan on staying in thailand and if you remit the money from your house. If you sell you uk house then dont remit the proceeds in the same thai tax year (if you stay for over 180days) because then you could be liable for capital gains tax in thailand. If you use your money a year later then you should be ok
thats not entirely true it depends on how long you have lived/owned in the uk and how long you have rented it out. You will loose a proportion of your capital gains allowance the longer you rent it out.
suggest you check your visa stamps. You will have been stamped into thailand for 90 days including your date of entry at the point you entered. The date you git from the embassy is that date you have to use your visa before it expires it has nothing to do with the stamp you are given when you enter.
Russell you are correct. Once your visa is approved you have 90 days to use it i.e. to enter thailand. Once you arrive in thailand you will be stamped in for the full 90 days.
Couple of things to consider. If you want a non O over 50 retirement visa and then subsequent yearly extensions its always better to get the visa in your home country before entering thailand as this will make opening a bank account more straight forward. I notice you say you dont want to deposit money in a thai bank account? If you want to do your own visa extensions you will need an account to deposit your 800kbaht for your first extension as you cannot use monthly income until your 2nd extension and then if you want to convert to monthly then you still need that monthly amount paid into a thai bank account. You can use an agent who could help you with the funding of your extension but then you may be tied into that method for a long time to come. You could look at a DTV soft power option to get a 5 year visa with 180 days stamp for each visit, here you dont need a thai bank account only your own in your own country.
An agent can only help you pull the information together in support of the application, they cannot get one like like can for thai visas in country, they have no influence over the outcome. Suggest you start by having a look at the uk visa website for the requirements to give you an idea of what required, she will also have to go to VFS in bangkok or chiang mai for biometrics at the point of application submission
As mentioned you need to apply for a non o over 50 retirement visa in your own country today!!!! If you want to have a chance of getting it approved before you leave for thailand as it can take from 5 to 15 days depending on the embassy. The rules have tightened a lot in thailand when it comes to opening a bank account which you need for your extension of stay when in thailand. You can open an account with your non O from your country so suggest you sort asap