I remember looking for this photo a few years ago, presuming that all photos eventually end up on the interweb, but couldn't find it.
Having re-read the account of her capture in Blood Knots by Luke Jennings I had another bash at finding the photo - and it was the author himself who had uploaded it.
The pike was caught in 1994, from Thamesmead by René Berg. And bottomed-out a 40lb set of scales, the pike has since been estimated to weigh 42-45lb, and is the largest pike caught in London - that I can find an account of anyway. I'm glad I have finally seen the photo.