I would say 6/7lb Andy, but it does not really matter regarding the weight. I lost a pair of Avon's three winters back while roaming about. My fault as I had not zipped up my rucksack properly and I've not thought to replace them. It's a cliche I know, but just being out is a what it's about.
A seen a thing on TV where people were to guess the weight of a Bull, when they added up the figures and worked out the average it was to within a few kg of weight, apparently that isn't a one off or fluke?
I've not got a photo with a fish of a known weight or I'd put it to the test, but if you have one why not try it out?
The fish was around 31' so I'm putting it in the 7lb to 8lb bracket. It was a typical Thames pike, slim but not skinny and fought twice as hard as the equivalent still water model! It didn't look like it had been feeding hard judging by the belly.
'Mona's' Weight for Length scale says 31" = 9.309lbs. Maybe there are more modern scales - Mona's Scale is based on the assumption that a pike of 40" weighs 20lbs which I think is perhaps not realistic