I don’t have phase 3. Do you need a phase 3 connection for anything over 7KWH?
Yes, you are stuck with 7.4Kw charger maximum.
you would need to 3 phase to get unto a 22kw charger which would be roughly 3 times quicker, but at your own cost and many cost many thousands of pounds as there wound need to additional cabling put in by your DNO
Also your vehicle might not be capable of charging any fast that 7kw on AC (or any future vehicles)