> The British Highway Code now includes the "Dutch Reach" car door open (where you grab the door handle with the hand furthest from the door to force your body to turn, hopefully seeing inbound cyclists).

Unfortunately, it doesn't work unless you're in a convertible type vehicle. Otherwise, the B and C pillars as well as the headrest will block[1] your view of an approaching cyclist. Checking the outside/wing mirror is sufficient. The British highway code also includes a provision that says that cyclists can ride in the primary position given the situation. Riding far enough away from parked vehicles to avoid a potential dooring collision is one of them.

[1] https://i.imgur.com/MuvTxOz.jpeg