If the 'client' hasn't used your company for 6 years, stop being a pr@t. If your subby hadn't got the work the client would have got someone else to do it. Obviously he didn't want to use you.
If you don't want said subby to do work for other people, employ him!
Wot 'e sed!^^^^^
Having been involved in heating system controls for nearly 40 years, the standard way is a 3 or 4 pole contactor with a 230v coil controlled by whatever timer that you fancy/suits your needs.
Put the fittings where they will give you the light where you need it. Don't follow the herd principle of nice symetrical lines, you'll regret it when you are working in your own light!
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc