Update. I have done more Internet searching and was horrified at the tales of disaster which I read. I was baffled by the many and variable boiling times that were being quoted and I decided to start with a lower number as I have boiled food in the microwave many times.
So, armed with my new recipe, about 4 small oranges, 1 lime in lieu of lemon plus sugar but no water i got the microwave dish ready and started boiling for 6 minutes on 850 watts, tested it and there appeared to be a slight set already started, but wasn't sure? Hence, I boiled it again for 3 minutes to make doubly sure - YES!we have arrived.This recipe and method only needs fine tuning for next time, tasted very nice and set beautifully. Thanks Helli, I think your magic word lemon did the trick or lime for me as it is easier to buy and very cheap..