I've just been speaking to an archaeologist in Oxford who told me about the discovery of a sizable henge monument in the city centre. Sure enough:

http://www.tvas.co.uk/news/oxford.html

The article notes that the discovery appears to fit with crop-mark evidence of barrows in nearby parkland. Interesting stuff.

Unfortunately, the site will soon be lost to building work.

(Apologies if this topic has been posted previously!)