(Sorry, I can’t manage to post in ‘comments’ section)
Those are amazing photos David and well chosen Oaks. They are the type of trees we need to record as veterans of Calderdale and very important as a record of past management and land use, as well as ideal habitat. 
Most appear to have been coppiced and then neglected, leading to those huge stems. Some may have just been damaged by the falling rocks. Generally speaking, in the past most of our local trees had to work for a living and our present idea of ‘woodland’ would have seemed quite alien.
To produce those gnarled and spreading trunks/branches they have grown in the open for a long while. You wouldn’t get that kind of growth in a closed woodland. Oak trees in particular need plenty of light and space, being a pioneer tree and depending totally on Jays planting the acorns in open spaces. 
We must cherish characterful Oaks such as these, try to understand them and prevent needless loss.