West Wycombe Hill Fort is worth a look and the West Wycombe/Hell Fire Caves too ... although excavated by local farm workers and Cornish tin miners around the mid 18thC it is likely, at least in part, to Bronze age.

There are occassional standing stones around that area including broken 'sarsen' in many of the local church's ... Chalfont St Giles \; the church is probably on the site of a much earlier symbolic construction and as such, what ever the construction was, it was smashed up and incorporated into the church.

Go to Harrow-on-the-hill too ... and do the Harrow Stone trail from Sudbury golf course to Stanmore Common, whilst not spectacular in a huge enormous sense, if in the area, it's well worth the trip.

In London, the London Stone opposite Cannon Street Station is worth a peek.