I was just going to add a point, then noticed it had allready been mentioned by the previous post. But to add to tamborines point, if, as they say, you were smoking, then the smoke alarms would have been activated at the time. As they obviously didn't go off , it stands to reason you weren't having a smoke.
Now here is the part that should be your saving grace, and secure not only your £150 refunded, but also a grovelling apology.........
By law, the hotel would have to have a log of any incident involving the activation of a fire protection device i.e. smoke alarm, as there was none, and no precautionary evacuation, there are only 2 possibilities, 1: you didn't smoke, and 2 : there fire and smoke detection equipment is faulty, and they are in breach of health and safety laws by letting the room out.
You should outline these matters to the hotel owner, demand your money back within 7 days or you will instigate legal proceeding, and then report them to the HSE,