Find my Device - Wifi on, feature set up, page says 'Off'

Ok, a bit of a breakthrough, quite unexpected, and not wildly encouraging initially as far as the feature (service?) is concerned.. but finally accurate with Wifi.

I have both my 32 bit upgrade installation, and a clean install 64 bit version as I'm finally biting the bullet and preparing for when I (eventually) replace this 6 year-old laptop. So far I've been using the 64 bit version since trying Find my device.

When I reverted to my 32 bit version, to my surprise, when I went to the site and clicked on my PC (which was shown- in grey- I think that's misleading as it doesn't invite you to click on it at all.. ) and when I did, Find my Device appeared in blue.

(Previously it was grey, and said 'Off').

So I duly clicked on Find my device.

It's location, however, was shown in Rutland, England's smallest county - which doesn't even include a city. (It's only about 17 miles x 18). No specific town- just a big coloured circle on the map. (I'm in Warwickshire, some distance away).

This morning: "Last seen at 28 November 2015 07:09:24 in Burton upon Trent, Staffs, United Kingdom"

Well, different county, maybe 30 miles away.

Noted the site says (I noted at some point) WiFi must be used.

So I'm waiting for an update using my Wifi connection.. which I've just got:
Last seen at 28 November 2015 07:26:44 in <my home town>, Warks, United Kingdom - and it's fairly accurate.. shown on the pavement about 20 yards from our house.

I've yet to retry on my 64 bit build where I first set this up.

So, why should changing the OS (and hard disk) make a difference?

And note it does need Wifi for accuracy, as I had expected.

Er, well, it's the other way round as I said.. it works with the 32 bit upgrade build, I've yet to try it again on the clean install..

Hi Brink, having had it work when I swapped to my 32 bit upgraded installation, I've now swapped back to my 64 bit build, and to my surprise, on the page 'Find my Device' was blue for the first time, and clickable. So for the moment at least- without changing anything -except swapping the hard drive in and out- it works.

So.. does 'Find my device' need kicking into action by being initiated from what might be perceived as a different device? Hmm. Odd.

Thanks for trying to help.. it's a new feature, so..