I popped along there today to take a peek for myself. It's about 25 minutes walk from my office.

TBH, I'm not convinced. It's a big old thing, and larger and steeper than most burial mounds I'm aware of (other than some of the Irish ones). It's also stepped, but that may be due to the landscaping for the ornamental garden it has become.

I'll be interested in anything you can dig up (sorry!) about it though...