Continuing from my reply on 6th Sep. I tethered my phone to another phone and then roamed in India and the mins then counted fine, either tethered or roaming, although I think they were still a few mins short. I therefore conclude the phone needs to be connected to the web.
On returning to the UK mins could walks plus a few mins, probably from walking round the house and office.
As for Apple stating the heard rate needs to be more that 110-115 that doesn't seem right. Checking my walks i vary from 104 up and the all count as walks.
To those loosing mins do you all have good signal and actual data connections during your walks?
Also do your mins fall short on day 1 or day 2 of no connection? I think there's a buffer of 24 hrs in the fone following 'no signal' because if I walk in the UK with no signal it counts correctly but in those cases I did have good connection in the 24 hrs before the walk.