Kd - you asked...
..."do you think that from your experience there are any traights that might seperate a good teacher from a bad teacher?"
Absolutely; the things that sticks out, especially for beginners in IMA's is your sifu's knowledge of body structure and being able to see and correct your faults. This is the perfect place to start.
you also said; "Internal arts club in Porthcawl (South Wales) researching the arts of SUN LUTANG". I have not had the chance to read it yet but.. You may want to 'supplement' your instruction w/ Tim Carmell's translation of Sun Lutang's books. I have heard good things about this book. I have read some of Tim's other works and they are very high quality. I am currently reading "Effortless Combat Throws" and it totally rocks. Tim's descritions of principles and concepts is excellent!
As for the three major internal arts, spelling may vary but.. Tai Chi Chuan a.k.a. Taijiquan - Baguazhang, a.k.a. Pa Kua.. and Xing Yi, a.k.a. Hsing-I.
Remember to relax and train as if you are in fear of loosing it