I just got an SETV in Bahrain. They required a simple statement letter from my employers in Saudi Arabia confirming the dates of my visit to Thailand, approval of the time away from work etc. The Bahrain embassy/consulate for Thailand provided a template on the website.
Yeah I've had two from Liverpool. You need to make an appointment but it's a same day service. I think i was waiting for an hour last time and they called me to collect it. Easy money. I probably spent the same in fuel driving there and back though