Hey Bond,
Thanks for writing in with a great question. Both the campaign data and the data in OSE are pulled from the same Mozscape index, but OSE defaults to page metrics, so you will want to make sure that you are comparing domain metrics to domain metrics between the campaign and OSE. When I checked the domain metrics between your campaign and OSE, the data did match up correctly. I may be able to explain the comparison better through screenshots, but I wasn't sure if you wanted to share your campaign information publicly.
The only thing I am seeing that doesn't show data correctly is actually the second competitor in your campaign because it is set up as ww.competitor2.co.uk, rather than www.competitor2.co.uk, which skews the subdomain metrics in the campaign link analysis. If you update the subdomain in your campaign settings, you should start getting better data for that competitor in the rankings and link analysis.
If you would like me to send you the screenshots to explain how the campaign compares to OSE privately, please let me know and I will email that to you right away.
I hope this helps!
Chiaryn