I accept that they have a job to do but making a driver nervous is not the best way to go in any circumstances, if I am on a dual carriageway I'll do around 50mph, a motorway up to 60 perhaps, I am on holiday so they could just overtake me, blasting the horn is optional, I drove for 30 years so I'm not in a hurry, on a single carriageway I might be happy at 30-40, so as I drive on my mirrors anyway, I will know if I have anyone behind and when possible or convenient I'll pull over, if it's a single track road then I will use the passing spaces, assuming some cretin hasn't parked in one and gone walkies.