Tray to use for sand play (ME14 near Penenden Heath)

This is another long shot as well as looking for a lockable cupboard to store sandtray toys, I'm also hoping there might be a school or nursery tidying and reorganising at the start of term with a spare sandtray that they don't need or have room for?? Growing Hope Maidstone is a charity providing FREE therapy for children with additional needs and support for their families (much needed due to long waiting lists for NHS therapy) https://growinghope.org.uk/maidstone/ . I'm looking for a sandtray, preferably on wheels like in the picture, but ok without wheels for the therapeutic play sessions that I will be running as a volunteer. Please can you help us to help children and families? Thank you so much!