Thanks for your reply.

You may need to get an ISO - rover connector, or it may be that the 416
already comes with an ISO style connector (anyone know this?).

Popped into Halfords to check prices and according to their chart it is just
an ISO style connector.

Just had a quick look at the head unti and just wondering what the trick to
getting them out? The last one I took out needed a key like tool in either
side but this standard Rover one.... can;t see any slots or anything.