I had a similar conversation with MikeR a while ago. If there are 4 1/2lb congers around South Sheilds Pier for example, then there is a very good chance that there are bigger ones, i.e the 4 1/2lber's mummy and daddy.
But like say Jim, they don't really get targeted in the NE. Few people, myself included, would drop a mackerel flapper in close off South Shields Pier or any other NE mark. I seem to recall some decent congers being caught at Cullercoats, maybe my memory is going the same way as my hearing.
Even small congers pull back pretty strongly and they are a good fish to catch.