Lite, as far as I am aware, all EZY stations use a DCS both at check-in, and at the gate. This is either e-Res, or the handling agent's own system.
There is however a slight difference between stations as to how they are used. Some airports, e.g Luton, enter the sequence numbers into the system as each passenger passes through the gate, and then check their passport/ID with the screen. Other stations cross-check the passport/ID with the boarding pass, and then enter the seq No's once the bulk of passengers are on board. In my opinion, it's horses for courses. Just two ways of doing the same thing. It really depends on the layout of the airport, and the number of staff available for boarding. I'll let you guess which one is used at STN
Given the choice, I would use the first option every time. Checking each sequence number in turn means that you are always on-top of the reconciliation process, and at any one time, you know exactly who is on board, and who is missing. But if you are the only gate agent, it could take some time!