As an active promoter of RNAV/GNSS (GPS) instrument approaches I'd make two observations.
On checking the UK AIP, North Denes does not appear to be a licensed aerodrome or heliport. It is therefore doubtful that CAA would consider any instrument approach procedure.
If they are licensed, which would include an obstacle survey, a RNAV/GNSS procedure would probably not be considered by CAA unless ATS is provided (ie ATC, or exceptionally FIS).