GPS12XL or GPX import issue

Whilst on the Easter break we did a lovely walk from Carbis Bay to Zennor and back. The weather was photogenic but ever so cold for the time of year.

The South West Coast east of St Ives

An undulating 20km hike seems like a fair training event and so I wanted to include it on Strava. I took my (rather old) Garmin 12XL along to record the track. I exported the data via serial port, converted to GPX and then uploaded to Strava. Now the 12XL doesn't include elevation data in the track which is fair enough but I get a rubbish travel time, so much so that my average pace is 10s/km.

I've looked at the GPX file, and tried reprocessing in several programs but even though the file looks sensible I can't get a better pace. I've messed with a test GPX file and can get a sensible time & pace on that, until I start to use by true GPX data! The XML format is pretty simple and I can't see how a basic file can be so problematic...

I'm not spending anymore time on it; the total distance is added to my total and the crazy pace hasn't upset my PBs. I've raised a query with Strava and we'll see if they come up with anything.