Parking on Double Yellow Lines on Private Road

[justchel]

This morning i discovered a parking ticket posted on my car windscreen for contravention (01) Parked in a Restricted Street during Prescribed hours. Myself and several other people park their car there as we have been told it is a 'Private Road' (although there are double yellow lines) with no signs displayed stating you are not allowed to park. I was under the impression that it is up to the Landowner as to whether or not you can park and that you therefore can not be issued with a normal parking ticket by a Civil Enforcement Officer.

Please can someone shed some light on whether i can content this parking fine?
Thanks

[justchel]

The road was built about 6 months ago and is owned by a museum on the right of the road - it was someone working there who told me it is fine to park despite the yellow lines as its a private road????