We clean a children's play centre and I am not sure sure if we should be cleaning the tables in the restaurant area and the high chairs, also they want the sanitary bins changed daily and put with the general waste and cleaning the nappy changing table, these are our health and safety issues at present. Please advise

What matters is what you have in writing.
If your contract doesn't have a specific list of tasks (or you don't have one!), then sit down with the owners and make one.
It's important in case there is ever an outbreak of a virus or bacteria. The owners are responsible, but it's still better if everything is exactly spelled out.

ANY fluid or solid waste from a person, child or baby is bio waste and should be contained, sealed and transported from the facility by a specialized company trained in bio waste disposal.

When you are handling this matter or fluid you should definitely use proper P.P.E. And dispose of it when finished in the hazardous waste container also.

This is for the protection of you, your cleaners, their staff and clients.

Stringer