Hi there CB1
You wish to do tower - good for you. Unfortunatley as has been stated NATS require more Area controllers at the moment.
you said that you didn't want to sit in front of a computer screen (implying Swanwick) what do you think an approach controller looks at??
If you go down the Mil route (been there, done that) you have more chance of getting a Tower/ Approach job but there is no way (currently) this can be transfered to the civilian side [through NATS anyway].
the other option is to self fund - but there are poeple more knowledgeable about that side on this board.
this job is hard whatever route you get into it - so be prepared for a lot harder work than you have ever experienced at Uni (i'd wager!!)
The decision is yours!!