I need to gain access to the Thermostat coupling under the top 'lid' of our Smeg A1-2SE, to exchange it for a new one; how do I fully remove the top ?

I think that I'll have to slide off the top LHS & RHS shoulders, before I can lift this off (all the small screws having been removed already) but I cannot seem to work out where there are any more screws holding these shoulders in place ?

Nick, November 2013