Whilst away last week I had the GPS on from time to time and discovered that mine reads 4mph quicker at motorway speeds i.e. 80mph displayed is actually 76mph on the GPS. Equally 37mph displayed is actually 35mph on the GPS. I am not worrying about this as I assume its just cable stretch and sort of normal (whilst bugging) and might stop me from breaking the speed limit in Guernsey (35mph) but now I know . . .

Definately take it back to be replaced. 20mph overead is taking the micky though and as you say, adding miles needlessley.

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DickyC

Gun Metal Grey 2014 XT660Z
'Advice is sought by someone who knows the answer but doesn't like it'

'The adsence of alternatives clears the mind marvelously'