ss wrote:

Light switch 2 gang both are 2-way.
The stair switch works ok at the top of stairs, at bottom stairs it only
works dependent on the position of the upstair switch.
I opened up and there appears to be a loose wire, can someone please
confirm that the yellow wire is needing reconnected as per image.

https://imgur.com/a/pnUTTWQ

Yes. (With a very high degree of probability, and little chance of
harm.)

--

Roger Hayter