Mismatch between Suunto reading of a file and GC reading

Okay, it appears the battery on my speed sensor had died before my last ride and my watch has 'fallen back' to using GPS for distance and speed (Its a Suunto Ambit 2S - sorry about that).

When I upload my data to Movescount and to Strava, the distance and speed tie up, and all looks well but when I transfer to GC, the distance is zero and its almost as if I hadn't moved for three and half hours.

I am guessing that in reading the data, GC is effectively saying 'there is an entry for the speed sensor so I will use that data' whereas the others ay, 'the entry is there but its junk, so I will use the GPS data instead'.

Anyone got a view on how i can force GC to ignore speed sensor data and use the other inputs for speed and distance instead ?

Looking at the data points from the flaky GPX file they look like this;

<trkpt lon="55.34697197377682" lat="24.851005990058184">
<ele>82.5999984741211</ele>
<time>2015-01-10T03:08:28.000Z</time>
<extensions>
<gpxtpx:TrackPointExtension>
<gpxtpx:hr>126</gpxtpx:hr>
<gpxtpx:cad>63</gpxtpx:cad>
</gpxtpx:TrackPointExtension>
</extensions>

And from a working data log is looks like this

<trkpt lon="55.3081529494375" lat="24.99813294969499">
<ele>42.79999923706055</ele>
<time>2014-11-29T03:08:05.000Z</time>
<extensions>
<gpxtpx:TrackPointExtension>
<gpxtpx:hr>127</gpxtpx:hr>
<gpxtpx:cad>72</gpxtpx:cad>
</gpxtpx:TrackPointExtension>
</extensions>

So where is GC getting its zero speed and distance values from ?

Thanks