This was the reason for my question, am I expecting too much? I had a Skoda Octavia before this and it had done 130,000 miles and never sounded like this one with 2,000 miles on the clock, this is my reason for asking. As for going above 3000rpm, well it's a matter of how you drive but for me personally I don't want to hear the engine sound like a transit every time I go to overtake, especially as it didn't sound like this before I took it for a decent drive. Thanks for getting back to me though.

I suppose I wasn't exactly clear with my post. I put down diesel knock but it's actually a tappet sound over the normal diesel sound. I'm going to take it to an alternative mechanic for a road test to make sure it's not just me! Also, I filled up at Tesco, so I intend to let the tank run down as far as possible and fill up with BP ultimate to see if there's a difference and I also noticed that the oil level has dropped to the half way mark. I don't know if it'll make a difference, as half way is safe enough but I'll ask the other mechanic whether I should top it up to the max. thanks to everyone for their input. I'll update the post with the outcome!