Here is a link to a company that sells an excellent but expensive tomato sauce substitute. I purchased this at a Toronto area health food store...but it is from the states and I think they ship it but maybe not outside of the U.S.

The ingredients are carrots, beets, celery, onions, lemon juice, citric acid and various spices.

I have tried to imitate this sauce with moderate success (my 13 y.o. daughter loved it so that is a good sign).

I used my food processor and ground up 1 med organic beet, 1 med organic carrot, 2 organic celery stalks, 1/2 large organic onion and about 2 cups water. I added salt and oregeno. I cooked 1 cup of organic brown long grain rice with this mixture for 40 minutes in a cast iron pan with a tight fitting lid...but quinoa or millet would work too (or amaranth...).

I served this with 125 g wild caught atlantic cod (baked for 20 minutes at 350 F with organic dried dill and organic lardons - ground ends from belly bacon - this is in imitation of the newfie method of serving cod) and baby organic spinach and a hemp oil/apple cider vinegar/cayenne dressing.