Any idea how should I wire shelly 1 to this 2 way switch?
Yellow is ground, blue is neutral and brown is hot/live.
I also have one additional live wire in this junction box, bottom right (grey) on the photo of box.
I don’t know what connection you require. If you want to control Shelly 1 it is possible to connect it like this
It looks like someone was rather liberal with wire colors, I see a green/yellow wire (typically earth) connected together with black (typically switched live) and purple (??) in a connector (top left).
The wire colors connected to the switch also don’t make sense to me, the green/yellow is connected to one “side” of the switch (marked “1”), I assume that the blue is connected to the other side of the switch (marked “2”?), which means that green/yellow and blue are used as switch wires.
I think that you can’t use the Shelly 1 here because there’s no actual neutral wire (but don’t trust me 
).
Can you send some picture of your setup you have? was it two way switch or one switch ? I am from NL too.
Sorry for late response. Its a two way switch.
I have a question because I have a switch in my kitchen with no neutral, I’m in the US to help. What I will prob be doing is getting the 1L and a bypass just to make sure of the 20 W because there are 3 lights and a fan with 3 lights that are on that specific circuit (there are more lights and such on the fuse). What I would like to know is if I can put the bypass anywhere on the circuit (any of the lights or fan) or a specific light. I ask because from all the schematics I find the bypass is on the last light before the switch which I have no idea which on the circuit is before the switch?