Ashton, you were right. It is not covered by warranty. I have just spoke to the guy from the garage though and they are being very good about the situation.
After assessing the manifold it seems one flexi has gone and the other is on its way, so have suggested a new manifold.
They have estimated itl cost £1500 to fit a new manifold, and have offered to put £1000 towards it as good gesture. I only bought the car 3 months ago. Think I have been quite lucky on this one.
So the next task is going to be finding a manifold as I've heard they are a rarity lol