Rear right wing mirror glass replacement

I have now had the Citigo for about 2 months now and after driving a VW polo 9N for 5 years i am getting use to the quirks of the car,but i got one dislike and that is the wing mirrors,if i have a car etc following me in the inside mirror the distant looks normal so 40 ft behind me does look like 40ft,however if i look in the wing mirror is gives the illusion the car behind is about 100yds behind which for normal roads is ok but on motorways etc i think it is bit of saftey hazzard is there any other 3rd party mirrors eg Halfords i can fit that will give me a more accurate looking  distance.