Hi all,
Looking for advice,
If I swap a single standard light switch for a double is there a module I can connect to the 2nd switch that allows me to monitor the position of the 2nd switch so I can control a device or bulbs in another part of the house ?
Yes, if you can completely own it (e.g. able to install esphome on it) you are obviously free to do that 
I expect both shelly and sonoff offering such types of devices based on esp’s, for example 