I have noticed recently that the rear spoiler and bumper has faded significantly in comparison with the other paintwork, it is a yellow VRS and I believe the fabia has a ten yr paint warranty is it a valid claim?

i had this on mine, but since getting hit my a motorbike and my car being in the body shop they are sorting it for me. Hoping that a full mop of the paint work will return it to 'new'!

I think its a fairly common problem just wondered if it could be up to Skoda to sort long shot I know

I have kept it polished but I think its paint on plastic so it has faded quicker

I would say it just needs a decent correction detail. The fading is down to wear on the lacquer which needs to be taken down. You could pay for a detailer to do the correction using machine polishers etc or you could try a decent t-cut (just make sure you protect it afterwards with a decent sealant and/or wax.

Paint warranty is only 3 years, so SUK won't accept the claim unless the car is younger then this. Anti-perforation warranty is 10 years.

As already suggested, try buffing the paintwork back up. I would have a go with some Meguiars Scratch X as it is not as abrasive as T-Cut and so less likely to damage your paint finish.