Anyone know what size Torq screwdriver is needed to adjust front washers please? 

Are the rear washers on the wiper arm a similar process. 

I can't remember the size but just get a set, they aren't very expensive. Easy to adjust don't put too much effort into it. The only problem is you can't adjust the jets individually on each side. By that I mean you can adjust the drivers side and the passenger side independently but not the individual jets on one side.

The rear, on the hatchback is the ball type so a small pin is needed to adjust, I have opened up the plastic shroud so the jet doesn't hit, this is now so much better as water now hits the rear screen.