How to Fit a Thermostat to a Worcester 24i Bolier?

Can anyone help?

I have a Worcester 24i boiler that had no thermostat. I bought a Heatmiser http://www.heatmisershop.co.uk/Manual-Dial-Type-Room-Thermostat-Heatmiser-DS1-L-p-16225.html.

Now the connections from the boiler are Live, Neutral and switched live.

Connection on the thermostat are Live, Neutral, A1 and A2.

The instruction give no indication of what should be feed into A1 and A2.

1. Remove the old thermostat to access the wires
2. Identify each cable and label
3. If necessary, strip the end of each wire (max 6mm)
4. Following the diagrams below, connect the wires
to the Heatmiser DS1-L terminals
5. Screw the DS1-L back plate to the back box
6. Plug the DS1-L thermostat front onto the back
plate
Live Connection L
Neutral Connection N
Heating Connection A1, A2
For 230v switching, you need to link from L to A1 and then
connect your switch wire to A2

I thought I would need a separate 230v feed but the instructions for the boiler state:

10.7 If a room thermostat and/or external programmer is to be
fitted refer to Figs 5 and 6. The devices must be suitable for use
with mains voltage.

Does then mean I use Live and neutral from the boiler to power the unit? if so where would the switch go?

This has baffled me I thought I had some competency in electrics.

Any help most most gratefully received.