I am sure that NATS posts people where they are needed. Lets face it, the people doing the postings are normal people who simply want to do their job and go home..
When I got through the interview process I wrote to ATCHQ and asked if I could please be posted somewhere in southern England as I had a young family and family ties in the area. I then wrote (honest!) "I suppose I had now better start bag-pipe lessons". Result was I was posted to Heathrow, which was my ultimate ambition...
Good luck with getting through the nausea first. Thankfully they never had that nonsense in my day or I'd be sweeping the streets..