Sorry to hear that, were they stolen from the house? There’s been a real spate of burglaries in Bristol in the last month or so, the police now seem to be treating this with the seriousness it deserves. Post this up on Bristol Stolen Bikes.
They are a bit obsessed though with the “followed home from Ashton Court” theory and are maybe mixing up cause and assocation. They’ve had some success nicking juves who’ve stolen decoy bikes from the street, but I’ve not heard too much good news about the more serious stuff unfortunately.
I’ve had recent advice from the police to install dusk til dawn lighting, lock bikes to a ground anchor even when inside the house, make sure your double glazing is properly sealed from the outside and get some barbed wire anti-climbing paint.
I hope you were insured?