See following links for info:
http://en.wikipedia.org/wiki/Shanwick_Oceanic_Control
http://www.nats.co.uk/text/82/scotti...l_centres.html
http://www.iaa.ie/air_traf/sha_map.asp
No problem organising visits to Prestwick. Call/write to NATS at Atlantic House to explain who you are and what you'd like to do and take it from there.
The new Ops Room
can be visited albeit briefly at the moment by those 'from the outside', in other words you'll get your head 'round the door for a peek and that'll be that. The engineers are still playing with the new kit, 'SAATS', and the training of ATCOs/ATSAs is currently being done in a separate area.
The existing kit is due to be replaced mid-Oct so if you're planning a visit and want to see 'FDPS' as it's known in action, you'd better be quick.
With the new kit being quite a bit different and still, how shall I put this, suffering a few hiccups, you may wish to wait until later in the year to let the guys/gals get accustomed to it before going to have a look. (I doubt very much if anyone would be too keen to have you sit next to them and then explain the workings of the system/airspace to you while they are still adjusting to the revised modes of operation that the new kit will bring).
There remains a slight '?' over the timing of the new kit 'going live' so check either back here or with NATS nearer the time of your planned visit to establish exactly which Ops Rm you'll be visiting and how settled the troops are with regard to chatting to visitors if the new kit has indeed been introduced.
C u soon(ish).