Your right with a 32a MCB for a 2.5mm flat twin and earth ring its just a standard circuit out of the regs .
Officially it’s part p notifiable as it’s a new circuit from the consumer unit, but if you extended the existing ring its wouldn’t be. This is why the part p is a waste of time.
I personally wouldn’t do a ring because it’s more cabling and they are dangerous if the ring becomes broken. 4mm or 6mm radial is much better.