Winster has patchy mobile phone coverage. Depending on where you are, you might do best with O2, Vodafone or EE. Or you may have no usable signal at all.
According to a BBC article, many operators will allow you to take back a new phone if you find that coverage is a problem - although time periods vary from 7 to 28 days.
For PAYG users, two exceptions to the mainstream operators are particularly worth considering. Tesco Mobile (who use O2 masts) are notable because they allow you to cap your spending (so no bill shock) and their Lite tariff (which takes a bit of finding) offers calls at 8p per minute and texts at 4p. At the same price (but using EE masts) is Adsa.
Winster Village Shop and Winster Post Office both offer topups for most mobile phones (including Tesco and Asda, but not GiffGaff).
If you have a poor signal at home, but need to answer (and make) mobile calls, then there are solutions available. The best solution is a box that spots when you are at home, and routes your mobile calls Broadband, and via the box to your mobile. For most, you need to register the individual phones with the service, although I have heard suggestions that the EE box will connect any EE phone within range.
O2 offers the Tu Go app for pay-monthly customers. Vodafone will sell you a Sure Signal device for £69. EE offer a "Signal Box" device (apparently available in their retail stores, but they don't give any details online). Three have "Home Signal" - which they give to some (monthly contract) customers - there doesn't seem to be the option for PAYG users to purchase one.
Some mobile operators also offer a wifi-based app for smartphones (eg Three In Touch) - this doesn't need a separate box, but it may mean that you have to stop doing something else on your smartphone in order to make or answer a call.