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From the website answers your question : "In the evening you don’t even need to worry about small children (under 5 years old) as you can leave them in our supervised night nursery, though as there is limited space we operate on a ‘first come, first served’ basis daily. Opening times will be published on board. Please note that parents/guardians must ensure that infants left in the care of the Night Nursery are settled to sleep before they leave."
This appears to cover the points you have raised.