We went to Van Hage today, not for the first time, but I really think it deserves a mention as a great (and FREE) family trip out. In addition to things you might typically expect to find in a garden centre there is a lovely animal garden. They have a range of animals there and offer opportunities to interact with some of the animals at weekends and during school holidays (see website for details). There is even a miniature train ride (small charge of 80p per passenger applies).
Definitely worth a visit! See website for more details of events and activities http://www.vanhage.co.uk/garden-centres/great-amwell/