I’m trying to work this out for my own needs based on 285 miles per full charge (77kWh).
77kW from charging at home @ £? kW (estimate 10p kWh = £7.70)
170 kW Tesla Charging £88.21 + £8.99 = £97.20
247kW in total / 77kW (car capcity) = 3.2 charges for journey
3.2 x 285 miles per charge = 912 miles total
£104.90 total cost for journey of 912 miles = 11.5 pence per mile