Dave Plowman wrote:
2) Do I need one? My I have earth bonding to the gas and water pipes
which I guess can work as an earth. But is that safe?
....
The snag comes if and when the external bits of these pipes are changed to
plastic. Assuming they are not already. But using them as an earth hasn't
complied with regs for a long time.

The intention of bonding supply pipes together is to ensure that the
consumer side of those pipes is bonded to your electrical earth, not
to use the incoming supply pipes _as_ your electrical earth.

JGH