It’s very much down to the the owner what they charger unfortunately and whether its a HA. LA or private run. HA & LA’s have started installing 22kW chargers where they have office’s on site with authorisation cards for the residents at discounted rates. If its privately run it may be included in the ground maintainence or could be per kWh but, pricing is anyones guess. Have you tried to google the site or look on zapmap?