At the moment they are a good 4-5 cm long and are dropping off the Willows one by one and heading across the garden looking for a location to pupate. I'll look forward to a decent catch off Buff Tips in my trap next summer! Below is how they look now and this is a photograph of an individual that I took on Gail's hand that was heading out across the garden in search of a pupation site.
The forecast is looking as though it should be mainly clear over night, although there is still the chance of a shower or two along the coast, with the wind starting SE at 0600, becoming E by 1000 and NE by 1200. That's the forecast on the BBC, but rather confusingly XC shows it being W - NW. Ah well, I'll just have to get up, take a look and decide whether to bird or ring, or both. Whichever it is I will be at the obs.