Have you looked it up in Lockyer's Farm strip guide or the like? If it's anywhere, it's probably there as it lists loads of little strips that don't feature on any charts.
If it aien't in there, chances are (unless it's a really recent build) it's a private strip as in private/my playground/no visitors/go away. We've got several unlisted ones like that on the south coast - one of them looks really immaculately kept.