The membership pays their dues therefore the membership has the right to make policy.

Sounds reasonable, but imagine this:

RULE 42. Any member of this Party shall have the right to remove goods from any retail outlet of their choosing without making payment, and without being penalised for this.

No concern of anyone but the members?

The point at issue with regard to the BNP's Constitution is exactly the same - not that we don't think it's very nice, but that it may be illegal.