glasgowdan writes

I'm confused now. Don't most people use orange cables to plug in their
lawnmowers, strimmers etc?
I already have an external socket on the
wall. It's to run a fridge freezer in the shed. If I can plug this
extension into the external socket, fit a conduit and bury the cable
myself that would be the ideal solution as it's simplest... what do you
think?

When you use an extension cable for your lawnmower, you are acutely
aware of where it is, and you look after it very carefully, and check it
for damage after every use.

If you bury the cable, not everyone in your family will know exactly
where it is. Someone could cut through it with a spade, it could get
damaged with movement of the soil, rodents could gnaw through it .... It
would only need a small amount of damage to the cable itself for water
to be able to get in. If you sell the house, the new owners may have
work done to the house; workmen may not know where the cable is and
could damage it or injure themselves.

It needs to be installed according to the IEE Wiring Regulations, the
current edition of which is the 17th.

With electricity (as with gas) the simplest solution is ideal only if
it also provides an adequate level of safety.
--
Kay