I think the original poster is asking if tax relief on subscriptions to a professional organisation (i.e. related to the employee's work) are tax deductible and, if so, the full amount at 20%, the full amount at 41% or some flat rated amount.
Off the top of my head. Professional Subscriptions paid on your behalf by your employer are fully exempt from BIK (ie tax exempt). The reason being that this is of the perks given to civil servants. Another example of this are computers. Civil servants can be given laptops but never Desktops, so laptops are BIK exempt but desktops are not!
Sorry, I should have given more details. If I pay say €700 p.a to a professional body of which I'm a member. Membership is necessary cost in order to carry out my work. Do I get a tax credit of 20% on the full amount or is it a €60 credit like the trade union credit?