Immigration is not on the list of areas in which Citizens Advice states they advise. Nonetheless, it's not a bad place to start to ask for resources. Perhaps they will help.
, I'm not trying to push you off, but this question might be better suited for a UK visa advice group. The people here will not be as familiar with the intricacies of the UK laws regarding bringing someone over. While certainly the nation of origin plays a factor in someone coming to the UK, the bigger issue here is UK law. I'm also pm'ing you.
Much as I fully support backpacking around the world (I wish I could resume my own version of it right now), I don't think accommodating backpackers is the priority of the Thai government right now. Its priority is protecting their people and that involves balancing two things:
1) Keeping infection rates low
2) Bringing in money
Neither of these priorities are really helped by backpackers. Yes, they spend a bit of money, but not enough to balance the risk. Also, backpackers are probably the biggest risk due to the travel.
Soooo...accommodating backpackers is not likely a high priority.