This way to Golden Cap

This sign leads you out of Langdon Hill carpark to either a circular (1 mile)  walk with the opportunity to join the South West Coastal Path and Golden Cap.  Today we are just doing the circular path which is fairly level as Jinxy can't manage much more at the moment.  The car park at this site (NT) has a £2 charge unless you are a member.
Halfway around this circuit is this piece of rock with this yellow thing let into it. (Extra). What ever it is I know not but people are already suggestions into it !!!!!!.  Suggestions welcome.