i have never owned these. what i would use it for is to film myself playing tennis as i have often produced shots i wold love to see back! with this and the head strap could anyone vrify whether this will be a good purchase or not?

thanks

Battery's not bad to be fair, but the two i've had (both Hero 5 Sessions) both overheated a few times too. Took the first back to Argos then bought another on ebay a few months later for a holiday and it did the same. Cooled down and starts functioning again after half an hour but it's not what you expect. You can also get a full Hero 5 from ebay (which also has a replaceable battery,) for as low as £300 if you put a regular search on.

Would this be suitable for a tough mudder?

Mines on order they sell for over 300 on eBay so it's a no risk buy

Have had no problem with the battery life. At this price I'm tempted to have another one!

Always wanted one of these but put off by the reviews of battery life. Have any existing owners on here find this an issue ?

great price, thanks OP. heat added

for those undecided this may help you
GoPro HERO5 Session Camcorder, 4K Ultra HD £289
GoPro Head Strap £15.99
GoPro Casey £49.95
GoPro Handler Floating Hand Grip £34.95

This is crazy good value! V tempted!