Cable for 2-zone central heating controller

[f0rmula]

I'm in the process of fitting new central heating, and I'm unsure which cable to use to wire up the thermostat. I'm using a PRT2-TS, and wiring it into a Honeywell junction box next to the zone valves and the boiler.

Controller:
http://www.heatmisershop.co.uk/epag...roducts/"PRT2-TS EU"/SubProducts/"PRT2-TS EU"

Junction box:
http://www.screwfix.com/p/honeywell-10-way-junction-box/66443

The controller needs the following lines:
Live
Neutral
Zone1 call for heat
Zone2 call for heat

I don't think there's any requirement for the cable to be heat-resistant. It's not running near anything hot.

The knockout box I'll sit the controller in doesn't have an earth, and nor does the controller itself:
http://www.screwfix.com/p/appleby-sfsb619-1-gang-dry-lining-box/44827

Question 1. Am I free to just use 4-core cable, and label the green/yellow with brown sheath?

http://www.tlc-direct.co.uk/Main_Index/Cable_Index/Flex_White_2/index.html

live - brown
neutral - blue
zone1 - black, marked with a brown sheath
zone2 - green/yellow, marked with brown sheath

Question 2. ... or would I need to use 5-core, and leave the earth dangling at the controller end?

http://www.tlc-direct.co.uk/Main_Index/Cable_Index/Flex_White_3/index.html

Question 3. ... or is there any more sensibly coloured 4-core cable available from somewhere I haven't found?

For what it's worth, I have a buildings notice out, and it will all be inspected by their electrical inspector.

Thanks in advance

 

[matt1e]

Use 5 core and terminate the earth into a connector block in the dry-lining box

Matt