Don't forget the National Identity card scheme has been abandoned and any money spent on them will not be refunded.......Oh and they will not be much use...
The citizencard is not the same as the national identity card. It was introduced mainly so that young people could verify their age when going to the movies or buying cigarettes and alcohol. Anyone regardless of age can get one and I think they cost around £15 and they can be quite handy to have. Not sure if this is what you were getting at but having re-read my original post I'm not sure that I made this clear.
One thing for the OP to bear in mind is that when you apply for a new passport you have to send your old one away with it. Even though some airlines accept expired passports for travel there will be a window when you are witthout (although I'm sure most people will have at least a couple of the forms of ID on the list HXdave supplied).