All the ones I have found in my research (Kiddopotamus, Shade a babe, Protect a Bub) seem to be for the actual pushchair / stroller / buggy, but not for the infant car seat that you put on top of it!
We are going to Spain for 5 weeks in August and it will be sooo sunny my poor newborn will burn if I don't protect her properly.
Thanks thanks thanks, Mumsnetters...