Adding fused switch

[rsgaz]

nitro, one trick you might not be aware of that might be handy...

If you use either an FCU or a 20A double pole switch(they do exactly the same in this scenario), if you get one with a neon indicator, you can wire it up 'backwards' on purpose so that the neon is always lit. Very handy to help find the switch in a dark garage. Totally acceptable to do it that way and only costs a few pence per year to be on like that.

 

[ban-all-sheds]

A double pole switch will do what you suggest.

And likely cost more.