Not last weekend, but the weekend before, CET Junior and I saw 4 separate cuckoos on the Medmerry marshes near Selsey. The first one I wasn't certain of, having never actually seen a cuckoo before - and having trouble sound-correlating call and flying bird. The second two were much more obvious. They flew overhead. The last one was on our way back.
Researching, it seems that two of the most preferred host nests for cuckoos to lay their eggs are Meadow Pipits and Reed Warblers, both of which are thriving now that they have reorganised the sea defences to the west of Selsey under RSPB supervision, so I guess that is good for cuckoos too.