Good Day

I bought a house last year and received a COC, but want to make some changes to my house to be a Automated House.
Because Laws and insurance so difficult to understand what is needed i do not want to carry on if i will waste my money and time to implement.
I bought the following to start with as i will probably build some units myself as i am a developer and electronics enthusiast:

http://www.ebay.com/itm/Sonoff-ITEAD...72.m2749.l2649
http://www.ebay.com/itm/86-EU-Sonoff...72.m2749.l2649

I want to use Sonoff to control my lights to start with, but not sure if i would be able to obtain another COC after changes have been done.

Could someone guide me in correct direction of what can be done and in what way should it be done?

Thank You