Winster has patchy mobile phone coverage. Depending on where you are, you might do best with O2, Vodafone or Orange. Or you may have no usable signal at all.
According to a BBC article, all operators except Orange 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, three exceptions to the mainstream operators worth looking at are GiffGaff and Tesco Lite (who both use O2 masts) and Adsa (who use Vodafone). These all offer calls at 8p per minute and texts at 4p each. Additionally, GiffGaff offers free calls and texts between their customers if you top up £10 every three months.
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.
O2 offers the Tu Go app for pay-monthly customers, allowing mobile calls to be routed via your home wifi. Vodafone will sell you a Sure Signal device for £100. Orange used to offer a device, but don't any more, nor do EE (but they are - they promise - working on it).