Insulation board / foam craft board (Makerspace PO21)

We are a community creative hub CIC that puts on art & craft courses. We need some offcuts of dense foam boards for a workshop, but we're not 100% sure whether it's going to work! Our budget is extremely limited for experimenting, so we're asking if anyone in the Bognor Regis area has any insulation board or expanded foam craft board that we could have to 'play with' and work out our strategy! We'd be incredibly grateful and we can collect in the Bognor Area most days. Thank you so much for looking at this post.