ok, my previous disaster was about not giving enough time to fresh veggies in the microwave. I discovered that I needed to add water, and stick the microwave on for 10 minutes.
For some reason, I thought that I needed to do this for frozen veg, too.
Half a pint of water in with frozen veg DOES mean that they cook slower, I found.
They lose all taste, though, and go soggy, and aren't very nice to eat.