As part of renovating my kitchen, I intend to have 2 applicances
(washing machine and dishwasher) plugged in to separate single
unswitched sockets under the work surface, with those sockets
controlled by switches on the wall above the work surface.

The switches will be on a 30amp ring circuit with a spur running to
below the work surface.

Looking at various old posts in google, people have recommended using
Double Pole Switches or FCUs for this task.

My undertanding is that both of these are double pole switches, the
difference being that the FCU has a fuse protecting the live wire on
the spur. Is this correct?

If so, which should I use?

Finally, I assume that both of these switches have 6 terminals - L,N,E
for the mains and L,N,E for the load. I then wire both ring cables
into the mains part and the cable for the spur into the load part. Is
this correct?

Thanks in advance

Will