Ummmm
Dont spend it yet,
If you look at
www.ir.gov.uk/manuals/eimanual/EIM32890.htm
The statutory fees and contributions and related costs paid to certain named bodies are eligible for deduction from earnings from an employment under Section 343, subject to two conditions:
1) the duties of the employment must involve the practice of the profession to which the fee relates and
2) the registration, certification, licensing or other reason for paying the fee is a condition that must be met before the person may practise the profession relevant to performing the duties of the employment.
In my humble opinion, I dont think BALPA membership quite fits those criteria!