I seem to remember that you have to have done the training for the night before going for your IR or CPL. If you do the IR first they want it on your license but if you do the CPL first you only have to have done the training nothing needs to be issued. Once you have the CPL pass sheet in you hand then you can start the IR no probs. And submit the whole lot in one go.
Give Dylan a ring at Leeds Flying school he will know the score.
I suspect the only chance you have of getting night training done this time of year is to go to the states. You will need to go to a 24H airport and then try and get an instructor willing to work at past 10 pm. So the likes of east mids might be able to do it. The open bribe of a couple of crates of beer may have to be put on the table, over and on top of the course fee to get an Instructor though.