Il get flamed big time for this but i always thought Edexcel wasnt too bad. OCR and OCR MEI just dont bother. When i say Edexcel i did business in it and it was an epic joke.
I wouldnt do it all in June, then you would just get CCCCCC, instead of concentrating on just three and getting BBB+. Its still a big step as you will know from your other a levels, and can take a few months to just get up to the standard. But personally, maths is my strong point and C1, C2 and S1 are very easy. Just do that then you already have an AS in Maths. So you can tell an employer your doing A2 in Jan 2011?
Hope this helps