2015 update: quite a number of adders have been seen around Curbar this year, some of which have behaved quite aggressively towards people. They are often very well camoflaged so it's worth keeping an eye out when moving into new areas, picking up kit etc as a bite, although not life threatening to most healthy adults can still be nasty.
Even though land above and below the crag has an Open Access designation, strangely the crag itself does not. See map here; http://www.naturalengland.org.uk/ourwork/enjoying/places/openaccess/default.aspx
All group leaders should familiarise themselves with BMC guidelines for group use, see here, http://www.thebmc.co.uk/Download.aspx?id=350