Turned up at Cambridge railway station to take the first train to unmapped territory. That happened to be Royston, the north-east quadrant. Sadly this was surveyed in the summer, but the person who did it lost interest and never did the data entry. So I resurveyed it today and added the data. That means my earlier assertion that Royston was complete to street/poi level now really is true.
Also popped up the A1198 from the north edge of Royston to join up with previously surveyed Bassingbourn about 2km further north, just to check nothing missed in the gap between - and there was indeed a short residential street off that road which was outside the village, so I'd missed it before.