Best WiFi dongle for Dumfries & Galloway?

Hi all,

I'm looking at a few different CLs up and around the Dumfries & Galloway area, in particular New Galloway.  Obviously I don't expect a CL to provide WiFi, so I want to go armed with the best dongle to suit the area.  I've not had much luck with the 'mobile network coverage' websites, as they all seem to indicate that there isn't much coverage at all in this area!  Can anyone local recommend a provider - EE, O2, Vodafone etc? Many thanks.