After British gas were too busy to attend, they suggested that I call a local tradesman because, as her carer, I didn't want to leave an elderly,disabled lady with no heating or hot water. After promising to come on Sunday afternoon, they arrived Monday morning. The engineer didn't have a clue what to do. He left an hour later, boiler in same condition as when he arrived. Another tradesman told us the problem and situation rectified in minutes. The problem, NO BATTERIES IN THE HIVE! My advice, if you don't know, don't come and certainly don't charge the vulnerable! !