Locking nuts are removed with the right socket, not with guesswork that rounds the nut and ruins the wheel. Bring the key if you still have it. If it has gone, say the make of the car and whether the wheels are alloy.
This job often sits on top of a puncture or a new tyre. The van carries the kit. Tight spaces on Portsea and on the Gosport terraces are normal; the work still happens at the kerb.
Once the nut is off, the tyre work continues as it would on any other wheel. The locking nut can be replaced if you want a new set keyed to the car.