Thanks to everyone who contributed heating design ideas.

The design is finalised and I am considering placement of the
components.

I plan to put the 40kW condensing boiler (Keston C40) and cylinder in a
cupboard at one end of the bathroom. At the opposite end of the
bathroom, 4m away, is the adjoining wall with my bedroom.

Is the boiler likely to keep me awake at night if I put it in this
location?