What further study would help in developing skills in business continuity or organisation resilinence? Looking at getting more qualifications in project management or change management, or does anyone have a recommendation that has helped them?

For: 
"What further study would help in developing skills in business continuity or organisation resilinence?"

You may check SFIA framework for identifying the skills and the skills levels, I believe with subscription you can get recommendations on the learning path.

For:
"Looking at getting more qualifications in project management or change management, or does anyone have a recommendation that has helped them?"

It depends on your current level of project management, however, I find it very useful to learn from Tools and official training of these tools, because they imply the concept with the execution, which gives you a push forward, then you can decide on the next step.

If you’re aiming for real future-proof skills in business continuity and organizational resilience, I’d shift the focus toward AI and AI-driven automation rather than just more traditional project/change management.

AI will be the backbone of sustainable, adaptive organizations and able to predict risks, automate responses, and pivot faster than manual systems ever could.
Learning AI strategy, automation frameworks, and data-driven decision-making will position you ahead of the curve.