According to
the AA route planner
Fleet to Sheerness is about 88 miles
Fleet to Warrington is about 212 miles
But then you need to take into account the trip back to the ferry etc. Doubt there'll be that much in it overall, so just pick the tuner you want and go there. I thought Tom used System-R to do his mapping?
System-R would get my vote but then I haven't used CPL so can't really compare the two.