Please post a GSV view of the approach to the signs, (asssuming GSV is sufficiently up-to-date to show them.) and update your thread as per the instructions above.
The approach suggested by John UK is probably the most likely to get all of the PCNs bar the first, cancelled. Essentially, you admit error, and submit reps based on mitigation. Being unaware of the restriction until the first PCN arrived needs emphasising. Your reps would need to emphasise being a new "P" driver and unfamiliarity with signs at this early stage of motoring career. This approach would hopefully restrict your liability to the discount (£65). No guarantees, though.
The alternative approach is to go in heavy on bad signage, (assuming we agree it's bad), but then your liability would be a lot more.
However, without more info. we're in the dark, basically.
