Bishop and Grainger saw off the challenge of the Canadians

Sarah Winckless featured in the silver medals won by the women's double and the women's quadruple scull.

But Britain's men's four - without James Cracknell, suffering from illness - could only take fifth in their race.

"Sarah did a superb job and the women's pair showed very strongly to win gold," said Great Britain performance director David Tanner.

In the men's four, Cracknell withdrew with a sore throat, ushering in Tom Stallard as replacement at the last minute alongside Matthew Pinsent and Alex Partridge.

"It seems to be us against illness and injury at the moment, not us against the Canadians or the Germans," said three-time Olympic gold medallist Pinsent.

"That's what's so disappointing. Being killed by seven seconds is not an accurate reflection of where we are. We know we can be the best four in the world."

In the non-Olympic boat classes, Ben Webb and John Warnock were bronze medallists in the lightweight men's pair.

Britain is second in the overall world cup rankings, behind Germany and ahead of the Netherlands.