There's a lot of myths around these guys, sure they were hard men compared to your average schmoe, but not giants that rips out tree with their bare hands. They're mostly fat, failed and overweight boxers that roid themselves up to look hard and swing wildly at their opponents. Any semi skilled boxer would smash holes in them. David Haye would more than likely have killed both Shaw and Mclean in a boxing match. Obviously it'll be different on the 'cobbles' but Shaw and Mclean only ever fought in a boxing ring.
During my uni years I once fixed the Sky of Lennie's late wife, Valerie. Wonderful woman she was. Spend 3 hours just talking to her. It was a couple of years after his biography came out. Heard a lot about Len but couldn't help but feel she was painting him a bit more dangerous than he really was.
Lastly, in my job I meet quite a few nutters. Worked with someone who's family was quite famous around the old East End. I cannot remember his name for the life of me. He knew all the old 'faces' as his dad and grandad used to knock about with them. He also just laughed at the reputation these guys painted themselves to have in their books.
Nonetheless, very interesting men and their books are highly entertaining.