Their exact statement is 'the department will consider applicants who resit their qualifications.' Reading between the lines a little, this does imply that there is no lower limit, but it is also hardly a promise - it's not exactly clear from this statement if they will consider you equally with non-resitters, though as A levels are only an entry requirement rather than part of a weighting, I would think - tentatively - they would...? Best to contact them directly, as always, but I wouldn't necessarily expect a response particularly soon!