I'm not sure whether SUAS do it differently, but ordinarily you need only have 3 semesters of your degree programme left.
Is archeology a 3 or 4 year course? If it's 4 years and you're only in your second year, there's really no reason why you couldn't join next time around - it wouldn't be a bar to joining either of the 2 UAS' in the NW.
Failing that, just go along to your nearest AFCO, get all the information you can, go to the RAF website and put in an application - the worst that'll happen is that they say no and ask you to come back later.