The house behind me had circular vents installed in their wall
yesterday and I am intrigued.

The vents are circular,cream coloured and about 8 inches across.

There are two vents approximately one foot below each bedroom window
and immediately below each is a short pipe, like an overflow pipe.

Can anyone tell me what they might be for - they have completely
ruined the look of the house as they are not the same colour as the
brick or windows and are really big, so they must serve a really
important purpose, I just can't think what.

Any suggestions?