Five little ducks

Spotted these ducks on the Water of Leith at Murrayfield this morning. They were causing quite a bit of consternation amongst the resident mallards and moorhens.
I've tried to identify them and would have said they were golden eye ducks except for the fact that the males should have a white spot under and to the front of their eye. The males' heads are a distinct green colour and rather beautiful. The females may have a crest on their heads which could make them tufted ducks but other things aren't right. The other possibility is a goosander as they have pinky/brown bills and pink feet.
Any suggestions?
They were very loud!