I found this rock at the weekend in the forest of Haigh Hall, Standish. It seems to be a solid mass of fibrous material. I have given it a scrub with warm water and a toothbrush just to get rid of all the dirt. the surface will yield under force from a screwdriver, as though it is some form of calcium mineral? My 4.5 year old son thinks it may be a fossil of some sort.
It looks too irregular to be a fossil. My 'first reaction' is that it is probably a bit of slag discarded from a former iron works. There are some metamorphic rocks that have this kind of texture, but Standish isn't a metamorphic area. Upon checking, I see that Haigh Hall is located squarely in the mid- to upper-Carboniferous of Merseyside. Because of the productive coal measures all around, this was formerly an industrial heartland, with many steel foundries and similar heavy industries (now long gone), so slag is my 'second reaction', also.
Maybe it is not the 'rock' that you hoped for, but you could keep it as a souvenir of Britain's industrial past.