50kW is not far off the speeds achieved by people charging over 80% in a Tesla.
I do have my reservations about this, namely, the UK has no where near enough capacity for the growth in just Tesla ownership (at certain sites).
The blocking of 2 bays by incorrect port usage is a big issue
Even though a small number of sites are part of the trial, it will confuse people into trying bays elsewhere creating issues for owners
It does not promote quality improvements in other networks. The UK is far behind when it comes to rollouts and other EV owners we will want to use Tesla stalls for their speed and reliability. (Other networks have awful amounts of downtime).
On the positive, 15 sites its an acknowledgement of an over utilised network in dire need of more capacity. The sites on that list are largely quiet sites, some have pockets of high utilisation.
I personally cannot see how revenue generated from charging after supply costs with create anywhere near enough investment to accelerate rollout. I still think it is more a morally weighted decision to accelerate EV uptake.
On the point of how they will monitor sites. They have expressed an interest in installing cameras to see how the sites in the trial are being utilised in practice. I dont doubt they will get this roughly correct, starting with just 15 is a positive first step, its a small trial on relatively low utilisation sites.
The only final point of concern is the excessively long process to sign off new sites or sites needing capacity upgrades (electrical mainly) in this country. It is a real barrier to growth if Tesla wish to double stalls in certain sites or create new sites. For example, Exeter can't come quickly enough yet it has suffered at least 6 months of delays due to power and planning. Trafford was built it about November I think, yet it took 4-5 months for sign off by the boffins. Far too slow.