If you look at the page now http://www.themodernantiquarian.com/site/7408 you will see that it is now flagged as being 'of dubious antiquity'.
The site type should still be selected so that people know that it's a dubious barrow or standing stone or whatever.
If you see a site that fits the 'dubious' category then just email the Eds and we'll look into it (asap).
Thanks
TMA Ed