Just to add to my growing list of minor irritations that spoil a good car.... XF 3.0 Prem luxury sportbrake, now at 3000 miles. I use the speed limiter nearly all the time - set just enough above the current speed limit to stop me getting flashed at by hidden cameras - and to avoid my tendancy to go faster and faster on a long journey because the engine's so nice. What is supposed to happen is that if you "flick" the rocker up, it puts the limited speed up by 1mph. If you roll it up and hold it briefly, the speed goes up by 5mph. If you keep holding it up, the speed limiter keeps going up in 5mph increments. Same on rolling the switch down to reduce the speed . What actually happens is that if you "flick" it up, sometimes it responds and sometimes it doesn't. If you roll it up and hold it, sometimes nothing happens at all, sometimes it responds after a short pause and sometimes it pauses and then ticks up the 5mph increments quickly and overshoots where I want it to be. The switch itself feels very soggy and not at all positive. Initial supplying main dealer response (after I demonstrated it with the car static) was that they'd never seen or heard of that before, so they changed the switch. That didn't help, so they changed it again. Now they are out of ideas.... It's either a duff batch of switches, or an inherent issue with slow response from the system (wiggly amps getting lost trying to find their way round the databus), or me being a half-wit. Constructive suggestions welcome!