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.

The building committee is determined to persist with subsidies, and the
council has said that we need to either move the current gas
installations to the back of the building - which is completely
unfeasible - or replace them with electric ones. Within 7 days.

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?