I wrote a short blog post a little while ago on preventing low back pain with exercise. I think your problem area report might have missed several important meta-analyses on low back pain. In particular, Huang et al., 2018 and Shiri, Coggon and Hassani, 2017 seem to supersede Steffens et al., 2017, and Lin et al., 2018 seems broader and more recent than NICE, 2016. I think your assessment of the quality of evidence in favour of exercise interventions for low back pain might reasonably update with respect to these references.
I wrote a short blog post a little while ago on preventing low back pain with exercise. I think your problem area report might have missed several important meta-analyses on low back pain. In particular, Huang et al., 2018 and Shiri, Coggon and Hassani, 2017 seem to supersede Steffens et al., 2017, and Lin et al., 2018 seems broader and more recent than NICE, 2016. I think your assessment of the quality of evidence in favour of exercise interventions for low back pain might reasonably update with respect to these references.