Just about to cancel a Vodafone contract under their 30 day Satisfaction Guarantee. It seems that pretty much everywhere I go, coverage is around 1 bar or none. Recently I made a train journey that I've done many times when on O2. O2 had a couple of dead spots but Vodafone was a virtual black hole for the entire journey. Vodafone are suggesting a replacement SIM but that seems unlikely source of the problem. So how do others find Vodafone coverage?