Have you considered finding a CAA Doc who is authorised to do renewals and see if he can do you just the audiogram? They are usually open to doing private work and this would cost you considerably less than the full class 1, then if you fail you will have saved money, and if you pass I guess you could be pretty sure of passing the Class 1 when you decide to do it.
Alternatively, get the Class 1 audiogram test/ requirements from the CAA and find a Doc with suitable test equipment to put you through it. Again, surely cheaper than a full Class 1. At least then you will know if you can overcome your 'stumbling block'.
Good luck
PP