This link site seems to have been established relatively recently to provide a feed from Crystal Palace to the Biggin Hill relay.

Located at the local BT exchange, the arrangement consists of a single log on CP with a horizontally polarised 18-element yagi directed towards the relay site across the valley. According to the various documents this is site 101.86 (also known by the BBC as "BHX") and is a transposer rather than an active deflector, but at very low power.