I have a very old Drayton Lifestyle LP522, one of the few devices I need to change the clock twice a year 
The device is connected to a combination boiler and megaflow and you basically configure it so the hot water and central heating system are switched on/off at set times during the week.
I want to replace this thing with something that can be connected to home assistant and which I can program remotely. Does anyone have a (cheap) recommendation for this?
I already have a Zigbee thermostat.
I have replaced the entire module in different stages. First stage was to find out the thermostat and replace that with a Shelly 1 relay. Then use a boiler component in Home Assistant to change the state of the relay based on the temperature of my rooms. The downside of this approach is that the thermostat was connected to the “ON” signal of the Heating output, so when I switched it to OFF, then it disconnected. This worked most of the time, but I couldn’t control the hot water as it was control by the Lifestyle programmer.
Then, next thing I’ve done is to use ESP32 (Tasmota) and AC relays to control central heating and hot water, however I’m still puzzled by the connections and how it works so I’m still learning on this one.