Hi Joe - thanks for coming back to me. Certainly sounds as though some good updates are on their way.
With regard to the WCAG testing, I am using one of the sites suggested in out Governing Bodies Accessibiity Guide - WAVE Web Accessibility Evaluation Tool (webaim.org). If you go to this webiste and put in our webiste address it comes up with all sort of alerts for issues I deem to be 'outside of our control' (albeit a couple of issues are directly related to our content).
I will certainly have a look at the 'Modern' Theme and see if this helps.
Once again, thank you for keep responding to these emails - for many of us this is a steep learning curve.