AWYRCYMRU - I think you should visit the tower & App room at CWL and have chat with the boys and girls there before you declare then to be "sometimes too far up their own a*se". I think you will find quite the opposite.
A visit to ATC is especially useful for student pilots, who a) are nervous about flying & RT and b) not as situationally aware about what is going on around them - a short tour of what does what and when and a demonstration of the kind of things which help them can be as useful as the opportunity to give them some feedback about your experiences. They're just a phone call away! It can be an enormous confidence booster to put some faces to the voices of authority. Do it this week.
Re: cr*p readbacks - from a pilots pov I believe that distractions in the cockpit/checks etc. are the very reason why ATC must insist on correct readbacks - if the chap is too distracted read back the clearance properly, how do we know he (or his mate) was even listening properly in the first place?
Excuses and explanations aside, proper workload management is an essential skill for airline crews, particularly (as has been pointed out) in safety critical situations like at the hold or when changing level. If you haven't got the required knowledge of CAP413, go back to school; if you haven't got the capacity or time to pay proper attention, then you need to learn better workload management and/or how to say "standby".
'Good enough' isn't!