Apologies Colin, not trying to diss your door edge protection idea, but a word of caution about them.
I used to use these many years ago and found that road grime and grit got trapped between them and the car door. This turned into an abrasive and eventually scratched the paintwork underneath. If you're going to use them, take them off regularly and wash/brush any dirt out of them.
If I needed to protect my door edges nowadays, I'd use either helicopter tape (which some might find an annoyance to apply) or clear Gorilla tape which is easy to apply and reapply. These tapes won't give much protection against damage from opening the door against rough surfaces e.g. brick walls, but they will give protection when opening the doors against smoother surfaces e.g. other cars.