The layout of the kitchen along the outside wall is boiler (freestanding with a fair gap either side), then electric cooker (again freestanding), then washing machine (again freestanding, but under a worktop/side supports, a couple of inches gap either side). The washing machine is also under a window.
According to my mother (who is 86, & often gets things confused), the engineer said the vent should go behind the washing machine under the window, however she didn't know *why* he suggested that (perhaps easiest access for him + drill?). I can't think of any advantage having the vent partially obscured by a washing machine and under a window. Behind the boiler is the obvious place to put it, but it wouldn't be quite so easy to get access from the inside, and the area is tiled (although after 40 years of boiler heat I'm fairly sure the tiles could be persuaded to come off the wall in one piece, and there may be a few spares kicking around.
There's obviously a safety angle to this, I think SG's quote for the work is very reasonable (£66), so I'm quite happy to have the work done, but not if there's no need for it.
I have two questions:
(1) Is it necessary to have such a vent in a situation where the vent can be provided via a suspended floor, or does it have to be directly through an outside wall? I'm thinking that enlarging the existing vent might be an option.
(2) If it has to be done, is there any reason why the vent should go behind the washing machine and under the window, when it could be put almost directly behind the boiler, where it would be less likely to cause a draught, and would be supplying air directly to the boiler?