One of my previous posts about 'a few years back' may have been a little misleading but that was out of a wish to not post too much information but seeing as you wish to know more..
I was a shunter (Train Person) for DRS from January at the start of this year, I then left DRS in April to take up a considerably better paid role in my previous career due to having a second child on the way.. Since then, an application to LNER has been in, processed, passed the medical and then withdrawn, again, purely financial based.. In terms of psychometric testing, I made it quite clear on the LNER forum that I only had to resit a single test, because although I had passed to a suitable standard for DRS at the time, it wasn't to the level that LNER required for that particular test..
The security check may well be what you refer to above, I don't particularly care for the detail of it as it is no longer relevant to me, but if its is the CTC then that's what it is called, all I know it was a lot of detail about family, background etc etc..
Anything else? I'll delete my previous post and apologise for slight misinformation but you must appreciate I was trying to pick things from my brain to assist.. not cause offence which I've obviously done..