When I turn the ignition the powervalve only moves a little bit and it sounds quite and laboured is this right or does it need setting up my friends 04 dt sounds like it moves a lot more when it starts up compared to my 2002

First thing to do is to open the cover on the eng and actualy look and see if it is moving full stroke and that the alingment marks are right.

When if ever was the last time you oiled the PV cables?

OK either the exhaust ports are full of coke, the cables are worn out and need replacing or the battery doesn't have the power. I'd take the valve out and clean it then work back to the cables then battery. The Yamaha power valve is a good design (unlike the suzuki version of similar vintage) and is easily stripped and cleaned. It should rotate with light and even force. I've had to use slide hammers on Suzuki RGV engines to get the silly split valve out of the barrel.

I haven't had the bike long about 3 weeks and I haven't oiled them so god knows when if ever they were done how far should it spin when the ignition is on