Do you have Mark Hill's book? The information in it is accurate.
On p. 113, he writes that the two illegible signatures found are either Eric Dobson, or Joseph Said, or somebody at the studio signing on their behalf.
Eric Dobson was Michael Harris' business partner, and stayed on to run the works until '85, after Michael left. He also contributed to design, in particular, the Tiger design is his.
I do have photographs of variations of these marks, not currently able to show them here, but confirmed by Ron Wheeler, whose site, with an example, you have found.
Signing things at Mdina was fairly random, it depended very much if somebody was available and had time to do it in the incredibly busy studio.
Your mark looks much more like Dobson than Said. I don't understand why you seem so unwilling to accept this from people who do know and are trying to help.
These goblets are popular, (they are a Michael Harris design), especially with a signature, and while Michael Harris's is clearly the most popular, if you are selling it, it will find it's own price on ebay.