So I needed to confirm the presence or lack of the Sandmartins on the site. I spent a total of 7 hours 15 minutes on the site itself.
Sadly I saw just four Sandmartins in that period. Not once did they try to fly into any of the nesting holes and only briefly flew around in front of the holes but that was because the wind blew them there. I checked all the fields etc but the short of it is they've gone. I did a quick email/tweet etc to people I knew who have active colonies, the furthest north is Northumberland and furthest south Kent. All have active colonies so have ruled out early migration. I've also rightly/wrongly ruled out deliberate or accidental disturbance. There's no 'commercial' interests now the planning application was withdrawn plus the site (parts of it) were handed over for public footpaths aths etc and trees planted etc so I personally believe the stoat came back and predated the young, possibly older birds too and not normally being a two brood species, they've moved on. I guess I will have to wait until next spring to find out, jeez! I checked every hole attaching a small torch to bamboo stick and had a look, no bodies, no eggs and no life, in all but two holes I could see the back of the hole so definately no birds. In front of some of the holes there's evidence of claw marks. As I watched the site I watched Crows settle just above on the ridge and peer over into the holes. Saw the Sparrowhawk fly in front of the colony and even the Buzzard and Kestrel flew over (ok Kestrel hovered) and checked out the colony. Not sure why the predators effected (if they have) the colony more this year then last year. After all I'm actually seeing the Kestrel and Sparrowhawk less this year.