Not sure why people are saying blackpool is a pain re id. Last two trips (post scare) I had no id - no problem - just the ticket you are given upon exit. With 3 pax.
Second time round they did notice I had less passangers than I arrived with - but no hassle! Just the usual security scan - I even had a usual toiletries etc in my bags. However you could get a bad day and I would suggest leaving any potentially controversial items on board and just take the minimum through security.
They really were helpful - and people should not be put off going there.