In response to your ageing query
As you know, ageing of Slavonian Grebes is not that straightforward, but the fact that this individual shows such variable patterning of dark (smudging) on the neck-sides and at the rear of the black head line and that the bill-base is particularly pale probably suggests that it is a FIRST-WINTER. However, it does have a bright eye and a pale tip to the bill, so not that straightforward (both construed as adult features by some)
PS - more images to follow when I get time to upload them Sunday evening
By the way, my sightings for yesterday at WILSTONE.....
The 2 Dabchicks, 49 Mutes, the 2 adult Whoopers, the 12 PINTAIL still, 3 freshly arrived female/juvenile COMMON GOLDENEYES, the BLACK-TAILED GODWIT on the bund, 2 Common Gulls, Jay, Great Spotted Woodpecker, 60 FIELDFARES, Goldcrest, Song Thrush, Redwing, 2 Greenfinch, a LESSER REDPOLL and 7 BRAMBLINGS in the Overflow Hedgerow with up to 70 Chaffinches (as well as a basking Comma butterfly in the car park)