To access the selected bit of Singapore Rd with a vehicle, you've contacted me about, you have to go through Tewkesbury Rd. To enter Tewkesbury Rd, you have to enter through either Singapore Rd at South or Talbot Rd at North, both of the entrances having signage of "Private Land" and ANPR Cameras, which can be as well seen on Google's Street View, although the signage is not that clear in those photos.

Yes, the PCNs are for accessing Tewkesbury Rd.
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            Published using OSMCha: https://osmcha.org/changesets/133949710
            