Thanks Josh. Got it working by doing this:
Move wp-plugins/pods/ folder elsewhere
Add plugin – Pods 2.3.18
Go to Pods – Settings – Cleanup & Reset – Deactivate & Delete Pods 2.x Data
Reactivate plugin
Refresh page
Run Pods Upgrade
Reason I could not do this with 2.4 was the the Template screen appeared broken – PHP not displayed in textarea and ‘Associate with Pods’ dropdown was broken.
Thanks for your help,
Ben