This is something you'd have to talk to Specsavers about. Polycarbonate lenses tend to have quite low Abbe values (which relates to the dispersion of light and chromatic abberration) the higher this value the better so although polycarb lenses are great in terms of impact resistance and UV protection, but some people will be aware of the chromatic abberration caused by that low Abbe value. They're also slightly higher index than the standard CR39 material that's commonly used. The higher the index of a lens the lower the Abbe number but you get the better appearance due to the thinner lenses and they'll feel lighter. I have a pair of high index (1.74 - highest you can get) and I find them great, but as I'm short sighted I tend to find anything that makes things sharper great. Hyperopes (such as yourself - I assume as you seem to have an aspheric lens) tend to be a bit pickier when it comes to the clarity of their vision as they often have managed for many years without specs (as they can change the focus of their eyes to allow for their prescription).
Aspheric lenses are great, they look fantastic especially when you compare the lenses to their CR39 equivalent. Unfortunately the peripheral distortion is a trade off with appearance.
I would go back to the practice you got the specs from and explain the situation. I would hold off buying online though as the accuracy of their glazing tends not to be as good and if you have a reasonably high prescription (plus or minus) the position of the centre of the lens relative to your eye is quite important as inaccuracies can induce significant prisms which can make things uncomfortable. I would give Specsavers a chance to resolve the problem. All practices aim to provide specs and contact lenses that leave the patient delighted, but should something go wrong it's easier to figure out where the problem lies. If you go elsewhere the liability of the problem is up for grabs, the online retailer will say 'it's the prescription' and I like to think optometrists are pretty good when it comes to this stuff so it's probably not that, and a recheck will probably confirm the prescription is accurate and the glazing or lens choice or fitting isn't accurate which leaves you with the online retailer.
