Rutty I have not had a chance to shoot one but have had a good play with the Air Arms and it is a quality peice of kit. I know a couple of shooters with them and they are both very ahppy with them. Admittedly it is not a Styer, but it is not that far short, and is a lot less. Although AA do not (well when I had a look) bring in the other grips ect, Edgar Bros import the CO2 version under the original manufacturers branding, and they have all the bits including left hand grips ect avialable.
I just had a look at the other gun on the link that you gave, as I had no knowlege of it, and have a very strong suspision that it is in fact the same gun.
Alan