Thanks everyone for the advice, considering the advice I decided to not
worry about the inverter technology and bought a Sanyo microwave,
unfortunately there is no way I am going to fit this or any other microwave
in my microwave space without breaking the clearance rules laid out in the
manual, obviously a lot of people must ignore these, same goes to people who
build home kitchens as my kitchen as a space designed for microwaves but in
practice it will not do the job, bummer. I guess my question is if there is
a person who fixes microwaves or has some other reason to know what minimum
standard clearances are acceptable, i.e are the manufacturers clearances
over engineered? The manual for the sanyo says 20cm above, 10cm at the back
and 5cm on the sides.