Yes, i've just replaced the high pressure power steering line myself as i'm out of warranty!!
Renault part cost about £300 (no way I was paying that) and the labour would have been loads as it took me over a day:
1. Remove all engine covers
2. Remove all underside trays
3. Undo High pressure hose at both ends
4. undo a few brackets, including the petrol tank bar and brackets holding air conditioning hosing underneath and front axle support bracket.
5. Somehow manage to get the line out twisting and pulling!!
6. Take to Pirtek who put new couplings and hosing on for £130 (still a bit steep but a far cry from £300)
7. Replace and refill unit.
8. Put all covers back on.
Mine failed an MOT because of it (bit picky in my view as most cars leak), but it's one of the most time consuming jobs i've done for a while, and I doubt Renault would have had the same care as I did.
Here's a few pics of the old line (put some red dust protectors on before transit to Pirtek):
http://www.flickr.com/photos/18136929@N00/476796409/
http://www.flickr.com/photos/18136929@N00/476796423/
http://www.flickr.com/photos/18136929@N00/476796417/