Final audition weekend
Sat 15/09/12:
9.726m inc HD / 10.308m inc HD & +1
* down ‒21.2% / ‒18.6% yr-on-yr
Sun 16/09/12:
10.173m inc HD / 10.605m inc HD & +1
* down ‒18.0% / ‒16.8% yr-on-yr [this is corrected from the last version where I got the figures a bit wrong

]
Bootcamp weekend
Sat 22/09/12:
10.452m inc HD / 10.893m inc HD & +1
* down ‒10.6% / ‒9.8% yr-on-yr
* up +7.5% / +5.7% wk-on-wk (compared with final Sat audition)
Sun 23/09/12:
10.968m inc HD / 11.472m inc HD & +1
* down ‒9.9% / ‒10.0% yr-on-yr
* up +7.8% / +8.2% wk-on-wk (compared with final Sun audition) [corrected]
Judge's Houses weekend
Sat 29/09/12:
9.718m inc HD / 10.212m inc HD & +1
* down ‒13.5% / ‒14.2% yr-on-yr
* down ‒7.0% / ‒6.3% wk-on-wk
Sun 30/09/12:
10.566m inc HD / 10.980 inc HD & +1
* down ‒18.2% / ‒17.9% yr-on-yr
* down ‒3.7% / ‒4.3% wk-on-wk
And a comparison of the change between the pre-recorded stages in each year:
Change from final auditions weekend to Bootcamp weekend:
2011: Sat: down ‒5.2% / ‒4.7% , Sun: down ‒1.9% / ‒0.0%
2012: Sat: up +7.5% / +5.7%, Sun: up +7.8% / +8.2%
Change from Bootcamp weekend to Judges' Houses weekend:
2011: Sat: down ‒3.9% / ‒1.5%, Sun: up +6.1% / +4.9%
2012: Sat: down ‒7.0% / ‒6.3%, Sun: down ‒3.7% / ‒4.3%