Did the Royal Navy plan enough minelaying submarines?

Why did the Royal Navy not build a larger minelaying-submarine fleet for a possible war with Japan?

It did field dedicated and mine-capable submarines, but Far Eastern range requirements made the task different from Germany's coastal campaign.

The question compares British preparations for Japan with the effectiveness of German submarine-laid mines against Britain. The Royal Navy possessed dedicated minelaying classes, and other submarines could carry mines in various forms. The operational distinction was distance: British boats might have to work from Weihaiwei rather than from nearby coastal bases. The Grampus class and HMS M3 provide examples of how submarine design supported the planned advance toward Japan.