What are some recommendations for a legit agency to assist with a UK tourist visa?

A user is seeking recommendations for legitimate agencies that can help with obtaining a UK tourist visa. A commenter suggested the agency 'Orchid of Siam,' which has locations in both Bangkok and the UK, noting their good experience with them for both tourist and settlement visas. Another commenter advised that the inquiry may be more suited for a UK visa-focused group rather than a Thailand visa group, and asked if the user is married to a British national.