Could be part of garden extension. There are several garden extensions in the area, most are plantings of ornamental trees or shrubs (there's an Oleander hedge nearby) or fruit trees; quite often these garden extensions are neglected and other plants pop up (for example in above mentioned Oleander hedge) such as privets, ash, nettle tree, African olive, Ivy, Honeysuckle.
much agreed! requires discussion of problem & decision by PCS to remove beforehand and a ranger on site. I had no success to win over the authorities to manage / discontinue / remove garden extensions and educate residents etc. For years I tried to contact residents with info tables, letter box drops, weed swap campaigns ..... I couldn't sustain lobbying, campaigning and all the ground work reaching 72 hours volunteering / week
It is so close to the fence it is unlikely to have been planted intentionally. I am more concerned about the 'garden escapes' hundreds of metres into the nature reserves.