Compass 2008 rallye Microwave fault

This is the model

Most microwaves are plugged in, in a cupboard near where they are

An intermittent fault on the PCB?

An interaction with the surrounding magnets, perhaps?

Or, it's had its day. I suggest managing without it until you get home and are able to extract it from its housing. 

If you cannot do without it while away  measure it they tend to be 850watt or all the ones we have had were/are 

See if there is an electrical store near where you are get one and change over when you get home

Ps it is not usual for them to be hardwired in an LV they are normally plugged into a socket near by

What amperage hook up are you on? Turn everything else off and try again if not on 16A.