We had some old pillows that came along with the old duvet that I used to insulate the loft hatch. We decided to use them for draft-proofing the chimneys because we’d looked into chimney balloons already (and bought one, before promptly losing it somewhere).
First, I had to clean out the grates and fire surrounds, with help from my sweep’s devil: 
I got a good look at the chimneys after clearing away the ironmongery. The chimneys are lined with a sectioned ceramic pipe, built in when the house was constructed:
I expected a rougher, square section, something a bit more chimneys of Greenknowe. A circular section, however, means a rolled up pillow goes in like a Pooh bear into a rabbit hole:
I did a couple of bedrooms, with the spare room to go. Guests in the spare room have commented on the chimney noise in some strong winds (“I thought you’d been stuffing pillows up there.”), with no hint of noise in the bedrooms I’ve done. This is promising; in the worst gales I get woken by the whistling winds in the chimney and less noise means fewer draughts.
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