Whilst speaking with the CAA medical advisors this week on behalf of one of my patients who also has a hearing deficiency, I asked this very question. The reply was that Class 1 approvals had been given in the past under old regulations, but that generally JAA rules require both ears & eyes to achieve the minimum standard.
Many company standard operating procedures now require that 'one ear is always off' and the use of intercom prohibited. This may cause you problems intially depending on which ear is OK, or may limit your career when the time came for a seat change.
If the deficiency occurs after the issue of the Class 1, then a more lenient approach is taken. As long as one ear reaches the minimum standard, then a 'practical cockpit hearing test' is undertaken by a senior company training captain to see if normal operations can be safely achieved.
For you I think that's it ! However, without wishing to start another highly controversial topic, from what my patients tell me (in confidence of course)
is that the job is certainly not what it was, and many are desperate to get out
Perhaps you could look upon it as a lucky escape, earn your money elseware and fly for fun. Good Luck.