Many people do overtime on bank holidays and many get paid more than normal hours. Also, when I was contracting I always knew that my hourly rate was supposed to cover holidays etc. so freelancers and traders should not be affected, just put your day rate up by 0.4% and you'll be covered for the extra day off.
Enforcing a shorter working week would increase productivity imo, as most people (and certainly "the bosses") wouldn't put up with a hit in their wedge.
Permitting, encouraging, or "forcing" people to work long hours is counterproductive (apart from masking poor management, allowing reduction in investment, and killing off the workers before they've drawn too much / any pension).................makes you wonder why UK PLC does it