Apparently when Mr Hutcheson got a big order he had a bunch of local lads he'd call on to work for him until the order was filled. When Frank visited him in 1990 he was making a couple of tanks a day for the classic blokes but only if he felt like it.
He reckons that at his peak he could put out 20 a day, sometimes more. Quaint stuff but it's typical of may of the stories in the British industry.