Yes but there's already a boiler there :(. Forgot to add on diagram.
Ah...Not a house :D (a flat on 4th floor) = no options on any exterior wall drillings.
We've got cooker hob on right wall (if facing west) and only way to vent outside is via current extractor fan. The shortest distance between hob and fan is diagonal at 3m.
1) Flat on building. Can't drill another another vent hole.
2) Concrete walls all around.
3) Can mount ducting kit on...