I am in a simular situation to yourself. Ive had a PPL since 1999, where i have slowly built up hours, ratings and experience, but finally bit the bullet and decided to follow my life long ambition and go comercial. I currently hold down a full time job, so distance learning was my only option. I looked at all the schools, but the choice came down to my personal circumstances and the need to complete over 3 modules rather than 2. Out of preference i would of chose Bristol GS due to their superior course material and online facilities, but have chosen London Met as they can deliver over the 3 modules/proximity to home. So far so good, as their course material is very comprehensive and support has been excellent.
good luck with your studies