Hi,
Its been a couple of years since I have flown in the UK but Im pretty sure you dont actually need clearance to fly through a MATZ, though it is in your interest to talk to whoever is there and asking is the safest airmanship wise incase there is a flight of mil jets screaming around.... I specificly remember my UK instructor telling me this....You do need to ask to transit an ATZ though....
Sure someone more knowledgable will correct me if Im wrong though,
Regards, SD.