If it is one of these www.gardenwildlifedirect.co.uk/.../the-nuttery.html you could try emailing this firm to see if they know if you can get replacement lids, or try the firm that makes them.
thanks Alan - yes that's it. I will try emailing the company
actually Alan following your link I then found the Nuttery site (under construction) so have emailed them direct too. Thanks
Well done Barbara good luck, let us know if you get a replacement lid.