Well technicaly it was only half the estate, the northen half. I took my mtb along with me so i could cover a larger distance than if i was walking. I've got a good bike mount for my Garmin eTrex. Covered 6 miles in total, but the time consuming bit was getting the camera out each time i got to a new road.

Thanks for the link, i can see some of my updates in the slippy map already. :-)