Can you read any model number on the control in the cupboard?
Copy and paste the link into your browser - go to page 10 and it tells you how to set it up -
When are you back over at the new house?
The RX1 only controls the heating to the house the hot water is controlled by the combi boiler itself so basically once the combi is connected to the electric supply when you open a tap the combi boiler notes a drop of water pressure and switches the hot water on. I will try and get you an instruction manual for the RX1 tomorrow and if you drop back in tomorrow evening I can send it to you.