Late Blackcap, or new arrival?

I dropped in to the car park and Bittern hide briefly this morning, 10 then 5 more Fieldfare went over low West, 2-3 Siskin over, 2 Meadow Pipit North, c10 Redwing, 1-2 Bullfinch, generally less finch movement obvious, but I wasn't out until 09:00, so may have missed early stuff? The walk down to Bittern hide produced a late male Blackcap, or was it a winter arrival since it was in sub song?