Hi. I checked under the machine on the plate. It is definitely EM4800. In my opinion it is not necessary to take it to a technician if you are careful. I have never pulled apart an appliance before like this but being careful and slow, I was able to disassemble the heating unit and take it apart. There was minor scale and no blockage. I could have saved myself heaps of time by firstly taking apart the pump which is incredibly simple- just a brass 12mm nut and a plastic hose and clip on the bottom. The pump then pops out of the rubber housing. I found that the pump (a little white plastic tube) has some kind of one way diaphragm (I think, because it only allowed suction one way) and some little tiny holes which were blocked with scale. I heated some vinegar and sucked it through and it cleared. You have to be careful when undoing the white pump tube as there is a tiny plastic bead in it which is part of the pump mechanism. The machine is now running again. Before this I pulled apart the switch mechanism on the front and nearly lost control since there are various plastic discs behind the black switch and if you get them out of order it is hard to work out how they go back together. There is an exploded parts list online which is partly helpful but not exactly accurate as it shows one part that is not the right shape and it appears in a confusing order (before the brass ring thing instead of after) and doesn’t show enough detail of orientation etc.
Anyway - all working well now.