How often destroyers and submarines trained together

Did Royal Navy submarine and anti-submarine forces exercise together and exchange tactical ideas?

Yes: destroyers trained constantly, with regular ASW exercises against nearby submarine flotillas and wider forces joining larger practices.

Submarine and ASW forces exercised together repeatedly in the Home Fleet and training flotillas. Destroyers were expected to conduct daily torpedo and gunnery drills and frequent night exercises. A month without arranging an anti-submarine exercise against a nearby submarine flotilla demanded an explanation to the Rear Admiral Destroyers. Larger practices could also draw in the RAF, Royal Marines, and Army. This cadence made ASW a recurring part of flotilla work and depended on an active submarine force able to provide realistic opposition.