Following normal wiring the first switch wiring does not seem to match second switch
That's true.
I imagine it used to, and now it doesn't, and that's part of the problem. Possibly caused by one or both of the common COM/L1/L2 vs L1/L2/L3 and the inverted/non-inverted triangle layout confusions?
and the second switch seems to have too many wires.
It's exactly what you'd expect for a loop-at-the-switch circuit. Paul - how many black wires are in that bit of choc-block -
is it 3?
The three core cable normally connects like to like so if red is in com as in first switch it should also be in the com in second switch but you have a yellow in that hole.
Indeed - Paul - the first thing you need to do is to identify the red, yellow and blue which are all part of the same 3C+E cable, and put them into terminals which match the upstairs switch. It doesn't matter which way round red & blue go, unless you're anal about switch rockers being symmetrical when the light is off, but the yellow must go in COM.
Nothing else should be in the terminals for that side of the switch.
Then, I suspect,
you'll be left with 3 reds & 3 blacks, which are the loop-in & loop-out cables for the circuit, and the cable to the hall light.
All 3 blacks should be connected together (
I suspect they are already).
It's possible that the red with the sleeving on goes to the light, so try that in L1 and the other 2 reds in COM.
If that doesn't work you'll need to try combinations of 2 reds in COM and 1 in L1 until you find the one that works.
Don't do any of this if my assumptions highlighted in blue are wrong.
when you switch the downstairs light to work the upstairs light the downstairs light goes out.
Plus when the upstairs light is on the bedroom/bathroom lights do not work until the light is off??
Have you just got one lighting circuit for the whole hose, not separate up & down?
If so and the circuit loop runs from the hall switch to the landing one then messing that up could explain those problems.
