Participante anónimo what country is that? Some embassies are in charge of more than one country, so they must vet applicants from several countries. For example, the Embassy in Santiago, Chile, also processes applications from Costa Rica and other Central American countries.
I've heard you can get a bank account even with a DTV if you "have a condo". Do you know whether having a condo in that statement apply both for renting/leasing and owning?
how so? DTVers aren't allowed to earn money in Thailand, so you'll need to eventually withdraw cash from your home country account anyway, before depositing it at a Thai account.
DTVers would always need to pay withdrawal fees, as we're not allowed to earn money from within Thailand. Also, your home country cards allow you to pay many things, so no need to carry cash, either.
As per applying in other country without being on it: it normally won't work, as they'll always request a proof of residence and/or that you're physically located there.
As per the visa, it seems they want to be sure you're "a resident" in the UK. But I understand that in most cases we can't just extend visas whenever we want. In Korea, for example, long term residents can extend their current visas only when less than 4 months remain on it.