all good, I'm working too and so you have waiting time too ?
No problem.
When I'm understanding all right
It have to be so.
SwitchA is the place where the shelly need to be fitted.
(I'm now using this pic)

SwitchA
Disconnect Com and put it at L from Shelly
From Shelly O a wire at Com
Disconnect L2 and put it in Com too
Disconnect L1 and put it at SW2
A wire from L1 or L2 to SW1
Switch C
(If it are the same Colors perhaps you need to check)
Disconnect L2 and put it at Com too
So it's nearly your second pic, only Switch C med there to be changed