Bourton Draining down

My wife and I will be taking delivery of a 2019 Bourton in a couple of weeks, and with the recent Covid Tier3 restrictions we may not be able to  go away in it if the situation gets worse and restrictions get tighter.
In this case I may need to prep it for winter storage.

I think the Heater is located in a cavity below the wardrobe, and I am wondering where is the Heater drain down valve and how do I access it? 
Can you Bourton owners give me some advice?

Some handbooks can be downloaded from the AS website. This is the 2018 Bourton which is probably the same as yours. You should find all the info you need.

https://orbit.brightbox.com/v1/acc-jqzwj/Auto-Sleepers/handbooks/handbook_documents/000/000/017/original/2018-Bourton-handbook.pdf?1560167392

The Bouton shouldn't be very different to the Nuevo I think.

The boiler is drained down with the Automatic / Manual Drop Valve which is located under the offside bunk.  Provided the non return valve is fitted in the correct position (mine wasn't) when you open the valve, Black with a Blue button and Blue knob on top, turn the knob to open, and open the taps all the water in the system is drained but not the water tank which is drained separately with the external Blue tap.

If I know dealers your van will probably be delivered drained down at this time of year for precaution. Take it to them full of water for the fitting of a bike rack and it will come back empty.

My Bourton heater draindown valve is in the box under the offside long seat. There are two white plastic caps on top of the box. The one towards the middle of the van has the draindown valve under it and the one towards the outside has the pressure valve for the water system under it so you can adjust if necessary. Hope you have small hands as access can be a bit tight through the caps.

There is a knob on the end of the draindown valve that you just turn. When filling up turn the knob back to the closed position but do not forget to push in the  round blue button you can see in the above picture or water will run out.

Is to all of you for your advice, It’s been a great help.I’ve also now downloaded the appropriate owners handbook from Auto-Sleepers.
Cheers,
Boggie.