So you can replace it any other shower pull-cord switch. Obviously not with a pull-cord switch that’s only suitable for lighting, as that would have a much lower rating.
Similarly your cooker switch can be replaced with any cooker switch with single socket. Subject to e.g. having enough slack in the wires in the back box to reach the terminals, i.e. some will be easier to fit than others in practice.
Is it just a coincidence that you need to replace the two highest-power switches in the house, or is there more to it? Note that the thick wires in both of these will make them more difficult to fit than other electrical accessories. Be sure to do it carefully, screwing the terminals up tight etc.