The Lollards were a political and religious organisation from the 14th - 16th Century. Herefordshire was one the main areas of support of Lollardy and a number of buildings in the Olchon Valley were said to be places of worship. The Olchon Valley was also the place where Sir John Oldcastle, a notable Lollard, lived and sought refuge after being declared a heretic. John Oldcastle was the basis for Shakespeare's Falstaff and was eventually caught and burnt at the stake.
At the initial location, look for the information board and the phone number for the Herefordshire Countryside and Parks Service, which is in the format 01568 ABCDEF
Using these numbers you can locate the cache, which is at N 51 5A.6BD W 003.01.(D-E)B(D*E) . It is a short walk from the car park and takes you past a ruined cottage, supposedly used by the Lollards