Like asking how long is a piece of string.
Every station is different, with the stability (and logic) of rosters being at the mercy of the competence of your managers. This, as I'm sure you can appreciate, varies widely.
Contracts may be permanent (mine was from day 1), or temporary, but all are most likely to be part-time as this allows the greatest flexibility from the team. Probably somewhere in the 20-30 hour range depending on the station.
Money is rotten, a mere £4.87 (ish) as a basic hourly rate. As a temp, you will receive no extra pay on top of this (guess why they emply so many temps!), but if permanent there is additional shift pay of 64p (ish) per hour, and other payments for Sat/Sun/night shifts. Quite easy to take home £750 a month as a part-timer without too many of the rotten shifts.
Shift pattern can be all over the shop as it is a 24 hour operation, and some of the mixtures can be absolutely awful if you have a clueless management team. Much as I despise them, I would recommend joining the local union (GMB probably) as it gives some leverage in obtaining something approaching practicality.
Depending on the local work patterns, expect 2 days off per week from any 7 (or combinations of 6 on 3 off, 4 x12hr shifts on, 4 off), with days off coming back to back if poss. However, again it depends on the management.
However, all said and done, an enjoyable way to pass the day, and a useful and occassionally interesting insight into the airline business. You get to spend a great deal of your time with the crews, which is good for networking and building up a more complete picture of the business. Most of them are a thoroughly decent bunch.
Flying ambitions and qualifications will be neither help nor hinderence I suspect, as most stations are usually short of staff due to the poor terms on offer and are likely to hire anyone with the inclination to do the job. Training is straightforward and undemanding, though the quality is highly variable despite the existence of a formal company-wide training scheme.
Whether the highly irregular and potentially unpredictable working hours will fit around a course of study (unless it is distance learning) is something only you can determine.