I have an old acrylic mid-blue cover from an MG Spring 25. I think it is about the right length. Only cosmetic problem is it has the boat's name on each side (Elan) - I guess you could sew on a panel with your own boat name to cover that. It also needs some shock cord along it's bottom edge for the hooks to secure to (the original shock cord has perished).
I'm working abroad until the 20th April so send me a PM with your e-mail if your interested and I will get back in touch when I return.