Whilst I don't feel the domain itself is that valuable, for what it's worth, here are two suggestions for building a website with this name, that could make you some money:
1) Build a website that promotes visiting English country houses. I think National Trust might have an affiliate scheme. Promote travel breaks as well.
2) Produce a guide to estate cars, and sell advertising on the site. Not easy this one, but could get you some AdSense clicks.
Rgds