Good morning Alex, I think getting a breadth of benchmarking data in operations of known "high hazard" activities is difficult but the trade bodies are the best hope. Perhaps think what you ultimately want to achieve with the output of the exercise? Is it as a basis to improve, or is it to justify not needing to improve? A common question asked of me over the years in both 2nd and 3rd party work has been "how do we compare to ..... ?" This generally is quickly exposed are "if we're less crap than the crappest were ok right?"... So a justification for inaction. The quest to understand where you sit between noncompliant and best practice sounds good but may well not be best served by adding the 3rd party component. I would instead think about what would a good aspirant level of safety look like for your company across the range of operations so your benchmark becomes "you today" versus "the best you can be". This documented effectively will allow you to document an improvement plan, assign resources and accountabilities, agree KPI's, etc. This process will be much more useful going forward as it is repeatable at intervals (as long as the datum delta of aspiration remains "current to future" and resists the complacency of retrospective acceptance of small gains). The benefits of developing this in house are huge. I would resist going out to the well known commercials who offer culture assessment type stuff as their assessment invariably finds gaps that their additional services are designed to close (and unfortunately even IOSH members Code of Conduct doesn't seem to address this unscrupulous behaviour in any way).