Gnat crashes (RAF losses)

Have just finished reading British Military Aircraft Accidents (Ian Allan) and was very surprised at the number of losses. There were about 33 crashes which seems to be a high number although I not sure how many the RAF ordered. A lot of problems seem to be with the Bristol Orpheus engine, was this an unreliable engine? Also there were many control malfunctions which resulted in the loss of aircraft so was the aircraft prone to problems or would this be an acceptable attrition rate?