The components are here: https://github.com/codeaholics/node-red-contrib-evohome
Unlike the Domoticz code, mine makes no attempt to learn about your config, so you probably already need to have identified all the things in your system, and their addresses, etc. in order to configure it.
The "receiver" node connects to a TCP port to read HGI80 data - I did this because my radio is connected to a Pi that's remote to my server and I use ser2net to expose it over the network. It spits out lines. If you want to connect to a serial port, I think the are other NodeRED components that will do that. You will need to split your serial data into lines.
Put the lines into an "HGI80 parser" node. Put the output of that into a "decoder" node.
You now have decoded messages! If you want, you can run them through an "InfluxDB formatter", and then put them into InfluxDB, but the schema will be the one I use which might not work for you.
There are some large gaps between my components and Dan's Domoticz code. Most notably, hot water stuff and controller mode. But it also has some things that it handles better - like battery info.
You'll also need a site config node, which just takes a giant JSON blob for now, because I didn't know what I'd want in the final version. It looks like this:
Code:
{
"controllers": [
"01:080777"
],
"zones": {
"1": "Basement",
"2": "Conservatory",
"3": "Master Bedrm",
"4": "Lounge",
"5": "Study",
"7": "Downstairs",
"8": "Bathroom"
},
"devices": {
"04:025896": {
"zone": 4,
"name": "Lounge Rad - Back Wall"
},
"04:025900": {
"zone": 7,
"name": "Downstairs Rad - Breakfast Room"
},
"22:167017": {
"zone": 3,
"name": "Master Bedrm Thermostat"
},
"34:011457": {
"zone": 4,
"name": "Lounge Thermostat"
},
"34:011469": {
"zone": 5,
"name": "Study Thermostat"
}
}
}
The config appears to support multiple controllers, but it doesn't really! 
The decoded messages look like this:
Code:
{
"original": "--- I --- 04:025896 --:------ 04:025896 30C9 003 0006FA",
"parsed": {
"unk0": "---",
"type": "I",
"unk1": "---",
"addr": [
"04: 025896",
"--:------",
"04: 025896"
],
"cmd": "30C9",
"len": 3,
"payload": "0006FA"
},
"decoded": {
"type": "ZONE_TEMP",
"device": {
"addr": "04:025896",
"type": "zone",
"name": "Lounge Rad - Back Wall",
"zone": 4,
"zoneName": "Lounge"
},
"zone": 4,
"zoneName": "Lounge",
"temperature": 17.86
}
}