If you've not got washer jets, I wouldn't bother Nicky.
If you have, then it can be done for under £1000 if you buy wisely and are lucky with Ebay as Ollie says.
I'm mid process myself and I've scoped out that I won't spend more than £900 even if I'm unlucky, although my vehicle has the winter pack, thus OEM headlamp washers on the car out the factory.
That £900 will cover Xenon headlights with ballasts + bulbs, the kufatec auto leveling kit and fitting at my local Porsche/VW Specialist, which then means my setup will be fully legal. Minus the washers and/or the leveling kit and technically (+ legally etc...) your cars not fit for the road MOT wise. Up to you though...
HTH's mate.