Ok so I have had a look at the route, remembering that if you plan a route in MRA basic you are using Open Street Maps as the mapping algorithm. This will differ in some instances from a TomTom map alogorithim. If you purchase the Gold version you can plan routes in TomTom maps (or Garmin Here equivalent) which will always be faithfully replicated on a TT device or any software using TT maps. There is also a useful function to be able to compare the routes created on one map type with another so you can easily see the differences in the algorithms the mapping software uses. It is important not to place waypoints near to junctions. In the case of WP 13 this in my view is far to close to the T junction and the actual GPS might easily think its a left turn here and hence you are taken to the west of Silverstone and not through the town. This also applies to WP 17 which I can see again is right on a junction. When you arrive at WP 17 you need to turn right but in fact the nav device can easily see this as a left turn. So you are told to turn left and go through the WP and instead of then requiring a "U" turn takes you on a loop back towards 16. As you have now been through 17 the routing then looks for WP 18 and determines the fastest route to it, hence why you are directed though Charwelton and not Woodford Halse. I dont think there is anything wrong with the software.What any nav device relies on is the accuracy of its actual GPS location and comparing it with the GPS co-ordinates of the next WP. To avoid these sorts of discrepancies keep WP's away from junctions, roundabouts and the like and allow the device a chance to navigate to the next WP. Hopefully this explains the problems you encountered.