I have RC, R, W, Y, G, C all of which I can see are covered.
Where I'm stuck is the S1/S2 - which I think are the existing indoor temperature sensors from the existing setup. But, what do I do with S1/S2? Tape them up then ignore them, or is there a way to use them?
Here's the terminal block and the back of the thermostat which I think is a Honeywell TH811OU1003 - https://customer.honeywell.com/en-US/pages/product.aspx?cat=HonECC%20Catalog&pid=TH8110U1003/U
The S1/S2 are for an outdoor temperature sensor, this will not be supported with ecobee3. We use internet weather instead based on your location details so just tape off these wires as they will not be needed.