No doubt in the slightest that it is a Harris piece. Just interesting that these are the only two pieces that I have ever seen marked 'Betty' and also the inclusion of the post Harris date on the chalice of 1974. So it would appear that 'Betty' was around from the early years, when your piece was produced and stayed on after the Harris's left, until at least 74.
Given that the name is virtually never seen, I did wonder if 'Betty' was perhaps an employee or family friend that worked in the shop or office and very occasionally signed the odd piece to help out during exceptionally busy periods.
Agreed, something with such a personal inscription would be unlikely to include the name of someone less known at the factory. However, I did wonder if 'Betty' may have been a close friend/empolyee who worked their, I would imagine it was quite a close knit place to work, especially in the early years. The Betty mystery continues.........
