Not all road borders are manned, I drove through a control on the way into CH but was not required to stop.
I exited into Lictenstein and the only sign of the border was a flag on the bridge.
The car and phone reconnecting to a different mobile provider were a better indication that I'd crossed some borders.
French customs looked in the boot (but not in my luggage) and I was passport checked by by the man in the union flag box in Calais and then once back in Dover I drove off the boat, out of the gate and onto the motorway.
I definitely recommend driving some mountain passes in CH, I did Gottard, Furka, Grimsel and Sustans in one day.