This is exactly what I've been searching for! I had my first session today as a walk-in, and it was an amazing experience. Kru LionHeart is an excellent teacher—he provides a very traditional and holistic Muay Thai class, which is exactly what I wanted. He even teaches some ancient Muay Boran techniques which was amazing to see and learn. He tests your fitness level, pushes you to your limits, and helps you with your technique. It was an extremely friendly environment. Everyone was supportive and patient, even though I'm a complete newbie and they are very skilled.
Just absolutely amazing. I highly recommend LionHeart Muay Thai to anyone interested in learning Muay Thai!