Sor. Vorapin Boxing Gym was established in 1979 by Khun Surapol and Khun Vorapin. The couple are well-known for organizing boxing bouts abroad and they have trained several Thai-boxing champions. They have two gyms in Bangkok, one very close to Bangkok's famous Khao San Road. The gyms specialize in providing Muay Thai courses to foreigners. These are well-established gyms that cater for hundreds of foreign students annually. They have all the trainers and all the equipment you need. Well worth getting in touch with them if this is where your interest lies.