The BALPA thing is seperate from the FREA.
You can claim 66.7% of your BALPA subs as per the letter.
PLUS
depending on which airline you work for and which local tax office you use you can claim a fixed ammount of tax relief for work expnses. Things like sunglasses, suitcases, flightbags medical etc etc.
These amounts vary from £470 from one tax office to £2000 from another.
Typical govt rubbish really.
There is nothing to stop you not claiming the FREA and submitting your own claim based on your expenses for the year. However you had better keep all of your reciepts cos you have to be able to prove it. The FREA is easier.