In reply to SophieEmily:
The Warehouse is fairly decent - they've got better at refreshing routes recently. There's loads in the Wye Valley - either as mentioned at the Chepstow end (Wintour's Leap, Ban-y-Gor, Tintern Quarry, & Wyndcliff), or Symonds Yat. There's also plenty of sandstone in the Forest if that's your thing.