in Sheffield/Chesterfield for car sat nav (GPS) units?
Anybody out there save me a lot of leg work, please?!

I have seen a sat nav unit for sale in Makro.

It is around £235 inc vat, as I recall,including UK map software. No wiring needed. A friend of mine bought one almost identical from Halfords for £360 !!

ALDI have discount sat-nav offers but only every few months though. You have to keep an eye on their offers and usually response from public is so good that you have realy to get there early to get one.ALDI (http://uk.aldi.com/)