Home Made Tomato Ketchup- sugar and gluten free

What do you do when life sends you tomatoes? Why, make ketchup, of course! There's no better way to use up a couple of kilos in one go, and once you taste the real deal, you won't want the stuff from a bottle any more. Plus tomatoes are such a healthy food; as well as vitamins and minerals, they contain lycopene which can prevent cancer. And the lycopene from cooked tomatoes is supposed to be absorbed better than that from raw tomatoes. Even the seeds have some nutritional value, containing small amounts of amino acids and minerals. There: I just gave you a perfectly valid reason for not bothering to sieve out the seeds from your ketchup...
This recipe is for a basic ketchup similar to the sort you can buy- but you could add different spices, and even some chilli to create your own unique version -I hear a little nutmeg works well- and maybe you could even use smoked paprika for a BBQ-y slant. Perhaps even green tomato ketchup would work; I may well be forced to try that one out should the present unseasonably cold weather continue and stop the rest of the crop ripening. So here's the recipe, which makes a large-sized jar full (the kind you get Barleycup in).
-Oh, and I nearly forgot to add that because this ketchup is home made there are no added starchy thickeners, so it's gluten free too. (As long as your compound hing contains rice flour not wheat flour.) But I'm rambling now; let's move on to the fun bit:

2kg fresh tomatoes (preferably organic and/ or home grown)
1 tab agave
2 tsps Himalayan pink salt
1/4 tsp black pepper
1/2 tsp compound hing
2 tsps tamarind concentrate (this is perfect instead of vinegar)

• First use a high-speed blender or food processor to liquidise your tomatoes. This way, the skins will get mashed up with the rest and there's no need to remove them. If you really want to get rid of the seeds, it might be better to sieve them out at this point. I didn't bother.
• In the shallowest pan you can fit them in (this speeds things up), and over a moderate flame, gently boil the tomatoes down to about half the volume, at which point it will be quite thick. Stir the pan from time to time to prevent scorching.
• Stir in all the other ingredients and check the flavour is to your liking.
• Continue to reduce down to a thick, gloopy consistency- just think how hard it is to shake the last bits of ketchup out of a glass bottle and you'll get it right. The whole process from start to finish probably takes an hour or so, but you can do what I did and have it on the go while you're in the kitchen making something else.
• Bottle your ketchup in a sterilised jar and keep in the fridge. And if you want any for yourself, don't tell the kids where you put it!