My current RRS has had a problem since new that at the extreme travel of the passenger wiper it smears a patch where the driver wiper overlaps it, the dealer says that it is just something that happens - is this a known fault, anyone?

Ive never encountered that. Is it possible you have some wax (or something similar) on the screen from when it has been washed? Either that, or maybe new wiper blades may help. 2010 TDV8

I have tried new blades and cleaned the windscreen well, it has been like this since new and has been back to the dealer several times to sort out but now they are saying that it is a known problem with the sport.

Yip! it is certainly known on mine. I find that it is OK with new blades but soon deteriorates to what is effectively an area that is not properly contacted with the blade. I recon I get about 5-6 months (depending on weather) out of a set of blades 'till this recurs. As you say been like that since new 2 years ago.

it's a real pain and very annoying as it's just to left of the centre of my vision and I find myself looking at it..... do you use a particular brand of wiper as a replacement - do you just replace the blade or the whole arm down to the drive?