The blowing and the signing were not neccessarily done by the same person.
Yes, m. Every signed chalice I've seen has had the signing around the outside rim of the foot. I have 4, (I had 5 but let somebody else have one) and have been quite interested in the chalices since ~ 2000.
I've seen MH signatures around the pontil marks, but those are from IoWSG; attenuated bottles and Seaward etc..
I've never seen any writing that scrawls across the body of the base like this before, from Mdina.
There is a lovely streak of silver swirling around the body of the bowl. This occurred when the gob of glass got slightly disconnected from the iron during the blowing, and silver metal gas escaped from inside it, to become deposited on the outside.
Originally an accident, it produced a lovely effect, so it was replicated on purpose. So the bowl of this chalice was made by somebody who could "do" that.
When it came to marking the glass, it was only done when and if there was time and the spare staff and equipment available to do it, or if a customer asked for it, otherwise it just got left blank. They had trouble keeping the shelves in the shop stocked, it sold so well.