Why Oxbridge?

Plus GCSEs have been made significantly harder (boundaries, not papers) for my year so I suppose that'll have an effect.

Don't want to be a "hater" but don't buy into all the media hype- the percentage of A*/A grades last year was only 0.2% less than 2010 and 3.3% higher than 2006 (looking further back, it was 5.7% higher than just 2003 for example).

http://www.guardian.co.uk/news/datablog/2012/sep/17/gcse-exams-replaced-ebacc-history-pass-rates (go to the table at the bottom of the article)

All that said, your grades are plenty good enough, especially seeing as you're at a comp so you should definitely give it a shot if you're interested.