I know it is not allotment related but came across these deals
http://mobile.talktalk.co.uk/sim
Can get a phone included for only slightly more
http://mobile.talktalk.co.uk/handsets/htc-desire-510-white
Just check you can get coverage in your area first- when looking at a phone for my Dad, talktalk says a signal indoors is unlikeley in his area!
They use Vodafone network. Personally not happy about them since there was something wrong with the transmitter here for months.
Talk talk took over bull dog for our ISP . Hmmm... I would be careful!