Thank you for the information @Ogleuk87 . I am sorry to hear you are facing this behavior and would be happy to try and assist.
If you have not already, check the breakers and switches at the location, to make sure nothing has tripped. Also check the boiler as it can sometimes have a separate switch on it. Confirm it has power, it should have a display or LED that turns on.
If it all looks good try and power cycle the Heat Link, if you're comfortable in doing so. Turn the power to the Heat Link off for a few minutes and then turn it back on. See if it has any reaction after, when you press the button on it.
