Replacing thermostat.

Hi,
I was looking to replace a 2 wire thermostat to a drayton easy 3s programmable stat.
Below is the wiring guide, was wondering if someone could advise me on the connections.
The L&N supply won't be a problem, its more the 2core coming from the boiler.

Wiring diagram:-




Existing stat.


New stat :-


Thankyou.

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Thanks for taking the time to look, appreciated.