I wish I could help...

I gave the lens a good testing today and it quickly became obvious that I'd been sold a pup. I took a couple of dozen shots with it and as soon as I loaded them onto my PC a soft band on the left side was apparent. Looking back at the images I took instore the demo lens was better but still not quite right I am wondering how the images seemed fine when they were shown to me but have clear issue when viewed on my PC...
Needless to say that this will be going back to Jessops for a refund, I'm not even going to bother trying to find a better copy it's not worth the hassle. I'm sure that 17mm is wide enough for almost every occassion.