@andré-faria thank you,
I hopefully wont be in a position to replicate again for another 12months, I was doing some extent mapping via a hovercraft; therefore used Sailing as the activity and the activity in question was in excess of 5hrs, be a while before I’m doing that job again in those circumstances, I personally think the software / firmware side got into a tizz; this can happy to a lot of hardware that has firmware installed to control the hardware.
As mentioned I will of course keep an eye on the situation and if I find the Bluetooth not appearing to broadcast again then I may get in touch with Support or just send it back (bought through amazon, so this is often easier than waiting on support.