That data includes PHEV and other cars.
While I acknowledge the SMMT sales figures are for BEV, I kind of struggle to make sense of them compared to what I see on the road and at chargers. If there are 3 other BEVs sold per Tesla I'm not sure where they are going. By logic there should be 3x more people using Public chargers than SuperChargers. Something doesn't really add up.
Anyway, go look at Norway, France and the Netherlands, no reason for their mix of cars to be different, and I'm not seeing pictures of frustrated Tesla drivers in front of SuC full of other brands. People's assumptions about what will happen are not being born out in reality. What we do know is that the SuperCharger network needs to keep growing, and the opportunity to grow will become constrained by government policy to open networks. Not opening the network would mean it would fade from significance, and we would end up using the other public networks with their availability times and payment complexities.