On 29/05/2007 09:36, Mike wrote:

There is only one T&E from the existing switch. However, it would be
easy to add extra cable(s) going from the rose to the hall switch

As the existing cable from rose to lounge switch is only 2core and earth
you can't get 2-way switching without either

1) Adding a new 3core and earth cable between the hall and lounge switches.

or

2) Replacing the existing cable from rose to lounge switch with 3core
and earth, and adding a new 3core and earth from rose to hall switch,
but you'll probably have 16 wires to terminate in the rose.

or

3) Investigate the wireless switch option.