I'm pretty sure the covers clip onto the nozzles and are on round pins so that they can rotate and sit flush when closed down.
You'd have to raise the nozzles (get someone to squirt them?) and then stop the nozzles dropping back into place when the water pressure drops and bend the brackets gently until they pop off.
So a 2 person job just to take the covers off. B***dy ford!
And you'll probably get wet :P