Has anyone found a cover to fit a Britax hi way (ERF seat)?

[tnml]

Hi, I just wondered if anyone knew of a cover (like the towelling summer covers) that will fit a Britax Hi way. I spoke to Britax and they don't make them for this seat, although they do for other models of theirs. I don't want to bodge something and find its not safe, but would like something to protect the seat from spills and things. I had a great towelling cover for my cabriofix which was really easy to remove and wash.