Is it safe to ground the light switch with just one cable?

[sparkwright]

Does it work?
Any pictures of the old connections?

 

[pete01]

Just looks like 2 switches that switch 3 things on and off to me.

 

[JohnW2]

Does the near switch maybe operate two lights on different curcuits?

As I've said, it does seem weird. It couldn't really operate two lights (or two anythings) 'on different circuits', given that the two upper terminals are linked together.

In fact, the functionality would presumably still be the same if the two lower terminals were also linked, effectively reducing it to a simple 1-pole 1-way switch?

 

[endecotp]

It controls two bathroom lights, a fan (which is an extractor system throughout the house) and maybe a shaving charger too.

OK, in that case the double-pole switch is believable.

 

[EFLImpudence]

As I've said, it does seem weird. It couldn't really operate two lights (or two anythings) 'on different circuits', given that the two upper terminals are linked together.

It does look like that at first glance but I think not:

 

[JohnW2]

It does look like that at first glance but I think not:

Yes, you may well be right.

 

[morqthana]

Thanks for the additional info - all makes sense. Do I need a specific terminal block to attach them together? Screwfix has different amps and sizes https://www.screwfix.com/c/electrical-lighting/terminal-strips-blocks/cat830486 and the ones I have from a previous job are 5A - 6mm2 - 330V.

If there's enough spare length to trim the ends back so that they are all straight, a Wago 2273-205 would be the easiest to find space for.