Is it actually british law applying around the whole of the coast or just a local sea fisheries committee byelaw relating to the issue of a permit? Also sea fisheries committee byelaws are only relavent to their district and are not enforceable outside that area and normally only enforceable by each committee's own warranted officers.
The MCA only make RECOMMENDATIONS as to how gear should be marked - if there was a law to this effect do you not think they would quote it in their leaflets covering this matter?
And I note you still haven't actually referenced the law(s) which you refer to... just where you have read it.