If hiring a club aircraft you may well need a cross channel check out with an instructor.
Otherwise the rules are as per schedule 4 quoted above.
I fly regularly to the Channel Islands and France and all passengers wear life jackets, I carry a PLB strapped to my life jacket and a raft is available.
I did an IMCR soon after my PPL with cross channel in mind as grey days make it very hard to tell sea and sky apart and it's easy to become disorientated.