I had a similar incident on a short haul, LHR - DUB flight a few weeks back. On the return leg i was in row 9, the emergency row.
After the push back was completed, and whilst the engines were still starting, I noticed that the pins which are slotted into the door to disable the slides in the event of an door opening were still in place.
This was the first flight of the day, but I would have thought during refueling and loading these would have been enabled for emergency evac.
I grabbed the attention of the no#1 and asked if "they always fly with the slides disabled". He gave me a wry grin, said of course not and within seconds there was another cabin attendant removing the pins.
I guess there can always be oversights, but if i hadnt said anything they might have done the flight with them in, although this is serious breach of practice, it doesnt nessisarilly need to be directed to the CAA.