Taking the latest quarterly figure (Q3 2015) and comparing to the peak Quarter for total production and for manufacturing (in both cases 2000 Q4), the fall has been around 13% for production, and around 7% for manufacturing.
Total production is down about 1% from the level when the Conservative-led Coalition government came to office in Q2 2010, and peaked post-crisis in Q4 2010. Manufacturing output is up 2.3% from the Q2 2010 level, but down around 1% on (the post-crisis peak to date) Q4 2014 and Q1 2015.