i say if you sent it in for a service it would just be a glorified PAT test , if its working its fine , you could have a look inside yourself (and post pics here ) to see if there are any wires melting or poor connections , and perhaps fill with a kettle descaler sometime , but that might not even be an issue .
There isn't anything to service in a magma. They either work or don't. There are two heating elements, a thermostat and some fittings.