Is there any tricks to clear the bonet jet? One of the 4 holes is blocked. Winter means you need lots of jets! 

A pin works well.
Regards
Barry 2017 Range Rover Sport TDV6 L494 SE Fuji White
2011 Range Rover Sport SDV6 L320 SE Fuji White Loved but GONE
2010 TRAKKA Motorhome Fiat Ducato GONE (What a dud, don't buy one)
2006 Discovery 3 SE TDV6 Automatic Chawton White/Ebony. Loved but GONE
2006 BMW X5 diesel White/Charcoal, Bought new, Gone after 12 years! Was Excellent.
Ex Member Range Rover Club NSW

Regarding not getting enough water on the windscreen besides having blocked jets.

I did not like the washers on my other toy - a Ford Territory Turbo (4ltr Petrol SUV 4wd for you in the Northern Hemi.)
Had experienced washers on Isusu Trucks and Merc. Sprinter vans where the spray nossles are on the wipers.
The RRS washers are not quite as bad as on the Ford but not that good either.
My solution was to buy a complete aftermarket kit and run it wired up to existing circuit. Then run tubing up and along the wiper blades. The spray nossles I used were from a garden kit (assorted spray patterns to choose from)and it works a treat. It provides extra water immediately in front of the wipers blades which cleans in all conditions and saves the blades and the windscreen as well.
I am thinking about doing the same on the RRS. Will post on the forum when I do it and if there are any problems .