Google search on Testors for the UK comes up with only a few suppliers, but it is available.
I'm going to do some laminating experiments out of interest with Plastic Weld, Mek Pak, Limonene and any other glue I have squirrelled away. Using up a sheet or two of styrene will be worth it if a conclusion emerges.
With a bit of luck I will pick up a Portrait today, I found a supplier based near where I have a meeting this afternoon, but I don't know if they are mail order only.
As a side issue, I was planning to go over to a Linux OS because of the withdrawal of support of W98 next month, unfortunately, it looks like Silhouette machines are not fully compatible with Linux.