The Derbyshire Caving Club web site. 

The Eldon Pothole Club website. (Based in Buxton in the Peak District.)

The Orpheus Caving Club web site. (Based near Parsley Hay in the Peak District.)

The Red Rose Cave & Pothole Club web site. (Based in Yorkshire.)

The White Rose Pothole Club web site. (Based in Yorkshire.)

The Black Rose Caving Club web site. (Based in Yorkshire.)

The North Wales Caving Club web site.

The Ecton Hill Field Studies Association web site.

The new Natural England web site.

The Peak District section of the National Trust web site.

Peak District & Derbyshire Team section of the (old) English Nature web site.

The Derbyshire Caving Association (D.C.A.) web site.

The Peak District Caving web site.

The British Caving Association (B.C.A.) web site.

The British Cave Research Association (B.C.R.A.) web site.

The Derbyshire Bat Conservation Group web site.

The ukCaving.com web forum. There's some interesting forums on this active site.

The Peak District SSSI Cave Conservation Monitoring Scheme web site. 

The Caving.UK web site. (Descent magazine.)

The Inglesport web site. (Yorkshire caving shop in Ingleton.)

The Bernies Cafe web site. (A great Yorkshire cafe and caving shop in Ingleton.)

The Caving Supplies web site. (Buxton.)