@matram Thanks for the info… I’ll give that a try tomorrow (fairly busy today)… I’m a software developer by trade, so am not scared of getting my hands dirty!
The only app I have is the Parkrun app (for the barcode at the end), and as it was a Parkrun, there was no navigation in play; the courses are pretty well marshalled and well detailed! The watch is paired to a chest strap for heart rate.
Luckily, the watch crashed after 4.95km, so I got most of the activity recorded, losing only around 15 seconds at the end. I didn’t notice any sluggishness - it was literally just as I crossed the finish line I went to stop the activity, and the watch was displaying the Suunto logo!