hmmm, tricky,
check planning permission for the fence was a good suggestion,
again try to reason with the neighbours as that seems the only viable option.
if all else fails, vandalize the fence in the various ways stated, accidental BBQ incident, hiring chavs to run through a few panels as if they were running from a burglary etc, just take them out while they're out - and deal with the consequences of having to put it back up again once the ferrari is out - once the panels are out and the car is removed the only thing you can do and they can expect you to do it to put them back - problem solved.