Just for the continuity of this thread and, I suppose, for statistical purposes, the bottom heater element in our Elson Coral E would seem to have packed it in after some 5 years' service (it was itself a replacement element at the time). We are currently using the booster function (i.e. the top element, I believe) as a temporary, but expensive solution for our hot water until we can get someone 'round to fix it. The new replacement element should obviously be without the built-in thermal fuse which was found on older models and which had a tendency of blowing and causing a very severe leak in the process.
10, 2 RQ
… but the temporary booster solution only lasted us until last Friday, when switching it on started causing our fuse board to immediately cut out. It has been cold water for us ever since :o, potentially continuing over the Easter period, as we wait for the spares to be delivered to the plumber, who will then fix a date with us for the job of draining the tank and fitting the new elements (assuming they are causing the problem – again…).