Dme bands?

From the uk. I was looking to buy the garrison dme reelmatrix kit but apparently I can’t buy it in the uk. Any idea where/ how I can buy it or something similar? Are there any other brands that do a similar dme ring that doesn’t involve a tofflemire retainer? It is a back tooth and I will struggle to get the tofflemire retainer back there so I want a retainerless system