Sorry, I don't know as much about it as I'd like. It's one of those places where the only way to see it is to go up a private drive and knock on the landowner's door and ask - something which I'm not very good at.
It's not a cave. It lies at the base of a very steep part of Stapeley Hill. I have seen it described as a small enclosure - or a fortuitous arrangement of stones which have fallen off Stapeley Hill.
Tim (Shropshire Traveller) calls it "the Giant's Grave - remains of a possible dolmen":
http://www.megalithic.co.uk/article.php?sid=2146412039
'though I don't know where he got that from.
Hopefully, we'll be having a look at it in June.
baz