You can get SCARTS with a breakout of the sound cables. These could be wired to the headphones by way of an adapter.
You need to look at the SCARTS on the TV and find which is an output (or Input/Output) - there should be an arrow moulded in to tell you.
Look here for suitable adapters, or search around Maplins, or the local TV shop.
Which one to use may depend on the headphone connections.