Do I need commercial insurance for my own car delivering Domino’s in the UK?

Hi all, I’ve been working at Domino’s in the UK for about 4 months. When I started, all I had to do was prove I was a named driver on my own car. They claimed they gave me third-party insurance for delivery driving, but it seems a bit dodgy to me.

Do I also need to have commercial / hire & reward insurance on my own policy to be properly covered while delivering pizzas? I’m just trying to make sure I’m not driving uninsured or risking my car.

Any advice from other UK drivers would be really appreciated!