I believe Gloucestershire Airport is a great Airport to learn to fly, It is very helicopter friendly and i believe is the busiest training airport in the country and as such provides a great environment for training.
I think that is the best argument for not training there - far too busy! Any place that can have VFR traffic crossing through its overhead above 2000' (without talking to Gloucester) whilst IFR (and often IMC) traffic is descending for an instrument approach is best left alone.
The training organisations that work there are all very good but the congestion is not.