Was it a lawyer that does visas?? I've sat in numerous visa agents offices, discussing my options, and never been charged for advice, the visa you apply for depends on your age, and financial situation to meet visa requirements, find out all your options, and then decide if you want to do it yourself, or get a visa agent to assist you.
Tim Gascoigne if the DTV can be obtained with a few cooking classes, or muay Thai classes, why would someone give all their financial information to the authorities of any country, how do you know they are not saving all that information, and could use it against someone that doesn't file a tax return, a lot of the digital nomads will just continue to hide in hotel room somewhere, and not do anything, the same as they have always done, who knows in a couple of years time, they may chase all of them, for unpaid income tax.
read the comments from an ex-border force officer, scan passport coming in, not going out, if you're not a wanted criminal, or of any interest to the authorities, it seems nobody takes any notice.
yes it's a £40 annual once a year payment, everything is manageable with your 1p mobile online account, my phone is duel Sim, both UK and thai Sim cards are always active, when you dial the number as previously explained, choose to make the call from your Thai SIM, it seems with AIS you dial "003" to make calls, dial as previously explained, whenever possible make the call with your Thai SIM, try only to use the UK SIM to receive free messages, for banking purposes etc etc, only use the UK SIM when absolutely necessary, because the last time I made a call to a UK landline from Thailand, it was £1 a minute with UK sim, do a Google search "cheap international calls with AIS" can help you to understand better.
Order a 1p mobile SIM card online, get it sent to a relatives address in the UK, get them to activate it, and send it in the post to Thailand, it's now £40 for one year, it's free to receive text messages in Thailand, what network are you using in Thailand?? I use the true network, if you dial "006" first, and then miss out the + add the "44" miss out the first "0" of the number your calling to the UK, it's very cheap, I've done it myself many times.