I've found coverage to be very hit or miss to be honest, the Android app gives you a map with hotspots local to you can be handy...
My local car dealer has "The Cloud" WiFi and its free and works very well. I gather Sky bought "The Cloud" company but I've not seen any Sky logos yet.
James BT Infinity 2 19/09/2012 - Estimate 44.6/6.5 - Install 52/12 - Actual 46 / 8 Mbps
13 years of broadband - 1999 ntl:(512k/1M)/BTbusiness(2M)/Metronet(2M)/Bulldog(8M/16M)/BE(19M/16M)/BT FTTC(46M)