I did both the City & Guilds Aviation Studies & Advanced Aviation Studies course (Ops/Dispatch) & can highly recommend it. It does make a diffirence if you get a good tutor (obviously that is in the lap of the gods), as on my course we got B742 & B744 simulator trip with BA at Cranebank plus a trip to Fed Ex Ops at STN care of our tutor. Thinks may have changed as I did my C&G course back in the early 90's, good luck if you go for it!
Wish me luck, I'm off to the States in October to do my FAA Dispatchers course.......