I tried freezing tomatoes before, but prefer bottling. I don't use Kilner jars, just re-use any kind of jam/sauce jars as long as lids are in good condition (not new!).
I use a pressure cooker - lids loosely on and screwed up tightly as soon as they come out.
You can also put into saucepan surrounded by boiling water.
I store jars in a shed- if they seal properly (you'll know if centre of lid is depressed) they'll keep for a year or more. No danger of food poisoning as acidic food like tomatoes, combined with the heating, doesn't allow any nasty bugs to survive.