Old continuous Lighting

When I came back from Paula’s she gave me some old Bowen’s continuous studio lights that she didn’t have room for ( I also dont really have room for them) However the material front diffuser socks have disintegrated, and so I’m looking for replacement ones. I need 18 inch diameter and NOWHERE can I find replacement ones!
Has anybody got any idea where I might find some?

Thanks in advance

Draco