If I do an extra year, will it effect my chances?

No, I'm doing that and applying to 5 'top 10' unis. I have asked each of them about staying another year at college, and they have said that they don't mind at all, as long as each of your a-levels are obtained within the normal two year period and your achieved/predicted grades meet their minimum entry requirements.

NB: If you complete your A-levels within the normal 2 year period and stay another year to retake a couple of modular exams to achieve higher grades then this means you will have achieved your A-levels within a 3year period which will disadvantage your application.

No, I'm doing that and applying to 5 'top 10' unis. I have asked each of them about staying another year at college, and they have said that they don't mind at all, as long as each of your a-levels are obtained within the normal two year period and your achieved/predicted grades meet their minimum entry requirements.

NB: If you complete your A-levels within the normal 2 year period and stay another year to retake a couple of modular exams to achieve higher grades then this means you will have achieved your A-levels within a 3year period which will disadvantage your application.

Have you emailed Bristol about it, out of curiousity?! I did that (doing 2 of the same subjects, but on a different exam board at a new sixth form) but they've not emailed me back yet!

Yes I called up the ECS department. Basically I've completed my A-Levels (maths, chemistry, biology and AS further maths), staying another year to complete FM to A2 level. They were fine with it.

I have a friend who stayed an extra at college and was retaking modules in all his subjects to improve his grades and he got an offer from Bristol to do economics.