Hi there,
Although i'm not a professional pilot myself i do hope to go that way and have wondered about hearing myself. Having looked at the CAA website for medical info i found the page for medicals below:
http://www.srg.caa.co.uk/pld/med/med...asp?category=8
It says here that if you can hear normal voice from 2 metres you'll probably be alright. There is more info there with frequencies and decibel rates but i have no undeerstanding. Good luck with the career anyway and even if the CAA is too strict you can probably get your PPL or go abroad to fly.
AA