Yeah they're mostly one of the easiest to grow, I'm across the sea from you (the Netherlands) so we have about the same weather, every year I start planting my seeds around March 15, and they go outside after May 15, it's usually when there is no more chance in temperatures below 0 at night, after that it's just waiting and supporting the plants because they can very heavy when they grow a lot of tomatoes and they collapse under their own weight.
Ripening your tomatoes also works without the banana, just put them in a bowl covered by a cloth of some kind, tomatoes produce a gas, ethyl I think that makes them red over time, banana's produce more of this gas, speeding up the process.
I definitely need to do a better job of supporting them next season. I had tea towels over the top of the containers to help with that. Very glad it worked otherwise it would all have gone to waste. Thanks for stopping by.