Needlesports do the one that not only covers Alferoide but the surrounding areas too. The cover of the Alferoide valley is pretty extensive though. Could be worth a look? Could even be a better bet incase you get bored of the granite slabs!
Would recommend the one in the post from needle sport or buy it local when you get there? It not only covers Ailefroide but lots of other great cragging in the area,
I live 20 min down the valley from Ailefroide so if you won’t any help or info get in touch
In reply to Frogger: I can lend you a copy of both guides until you get out there. I can recommend some routes and crags as well.
I go to Sheffield and the Peak regularly so get in touch by email.