The first piece is definitely Mdina, post Harris, as it is marked, but soon after. The colouring is very good, with shades of yellows under the amethyst. I don't understand how it could be confused with Whitefriars! The second is a good bit later, but still Mdina. I don't know when frosting came in, and I avoid frosted bits if I can. Just my personal taste, I loathe it.
If you get your sticky little mitts on Mark's book - a fantastic read, you'll find out the real story behind "who copied who" as far as the bark textured things are concerned, as this was actually not the case at all, it was more of a collaberation of two fascinated and enthusiastic artists at Whitefriars and Mdina, discussing new ideas together. The credit for the origin of bark textured pieces in the 20th century should probably really go to Timo Sarpaneva.