After walking for approximately 15 minutes, I reached Beresford Avenue (and asphalt, thankfully). There are two pedestrian entrances either side of the car park (again, locked outside of normal hours). If PR and LS did enter the park, it would've been more than likely via one of these. Whilst taking the latter imagine, I noticed a CCTV camera directly behind me attached to a garage. If it's working correctly, I'd imagine it's capable of picking up the entrance clearly. That said, its view of this area would be totally obscured if the bushes aren't tended to.