pull switch

I'm looking to relace a bathroom pull switch that currently powers a ceiling light and extractor fan. Not entirely what type of pull switch it is, as it seems to have L1-L4 + earth: Can anyone advise as to what type of switch this is, and/or which is best for the above solution? Thanks.

I think I know the answer to this but... I have overboarded (underboarded?) my bathroom ceiling, made a hole and pulled through the shower cable for the pull isolator switch. I think the old switch was just attached to the lath and plaster ceiling above, so no noggins / joists to screw into...