Thanks for all the advice guys. Given how well the car runs I'm not convinced it is the MAP vacuum hose we're talking about. I spoke to a mechanic today who, without seeing it, reckons it is much more likely to be the EGR valve vacuum hose that has been blanked off. Going to take it to my local...

It's a black hose with a blue stripe which ran as you suggested from the underside of a housing on the manifold to the fuel filter housing. The chipping has been done by the installation of a powerlink box if this helps.

Hi, I've just purchased my first RR, ( P38 2.5 DSE), and took it round to my local garage for a quick check by the mechanic. Although very impressed with the general condition he did point out that the ECU had been chipped and the throttle regulator vacuum hose disconnected and blanked off with...