bathroom venting through a chimney

[angliojoe]

Hi all,
Im turning my back bedroom into a bathroom and been scratching my head around how to get an extractor vent in as the external wall is over a lean-to roof and pebble dashed. The room used to have a chimney breast in it which has been removed by the previous owners, the chimney stack in the attic and the external chimneys are both still there, supported by a concrete lintel. Since the chimney is still there, is there any chance i could use a ceiling extractor above the shower and have it connected and vented through the chimney?
Are there any gotcha's i need to be aware of? Is it even allowed?
Thanks,
Joe.

 

[Loofah]

Nope. You'll create loads of moisture in the stack and all the nasties will start to leech through the brickwork into the room.
Just cut through the external wall and repair the pebble dash

 

[blup]

Use a ceiling extractor and flexible ducting in the roof void and extract through the side wall/ fascia.

Blup