I rang the agent before making my post. It's half an acre and the comment about no problem foreseen with planning permission is exactly as the estate agent told me when I asked directly about the circle.

It is for sale just as a 'site'. No PP has been applied for yet ,if it had FPP then I can't begin to think how much they'd want for the plot!

Are you local gjrk? If so please keep us posted when a sold sign appears and if any PP application signs go up on the site. I for one will be objecting.