The Caves of the Peak District Guide is a DCA publication, any royalties are collected by DCA. At least this means the money gets ploughed back into caving. I dont think the profits are anything to write home about anyway, COTPD is a pretty specialist topic.
As for website updates, if its a DCA book then DCA will have to handle updates. There are several sites that cover Peak updates and I dont think another one is needed. Its something that is bound to happen with printed but I think in the caving world, the effect is not too great. E.g. the white river series, titan, JH, sidetrack have all been discovered in since the last guide, however, just about every caver knows of their existance, has seen surveys, knows the location and may even have been down them.
I think for now, we just need to get the publishers to commit, and see where it goes from there.