Mad_Trev wrote:
This is the kind of thing that tends to happen in Spain, where I live.

The council came along to visit some work being down on the outside of
the building containing my flat, saw several flue pipes sticking out,
said that repair subsidies would not be forthcoming if they stayed, and
ordered the workmen to chop them off forthwith and replace them with
ventilation panels. This has had the unfortunate side effect that,
while the building looks much prettier, the boilers affected have
ceased to work.
snip
Since the council is believed to be happy as long as it looks as if its
edicts have been carried out, what we're looking for is a way of
venting the boilers which achieves a flat-to-wall outside profile while
allowing to-and-froing of air intake and exhaust in a way that will
satisfy the gas company when they carry out their next inspection. Any
ideas?

Most boilers have two means of fluing, either coaxial, or seperate piped.
If you replace the flue with the seperate pipe option, and put the
intake/outlet some 1m apart, behind the ventilation screens, with
ducting to