Thanks to you (and @Dan GSR) for finally tipping me into trying the iOttie car mount. I was highly dubious the first time it was mentioned.
I fitted it this morning. You are quite right. Very effective and a good piece of kit. I was very surprised how well it grips firmly on a textured dash surface in my car. Slotting the phone in and out very slick and it's generally well designed. Works equally well in "portrait" or "landscape" orientations.
Amazon UK link is here