I got some edge trim from Chilledpc but it's quite thick.
Its round 5mm diameter with a 1mm slot cut half way in.
I'm going to need some more if I'm going to do a case window and I prefur actual U-channel, but I cannot find any.
I found one place on fleabay but the smallest they do is a 3mm slot which is way too big.
I was going to order some more from Chilledpc and try to cut it down, but now it's out of stock.
Only other place I know of is mnpctech but that will involve long US shipping times and costs.
Someware in the UK must sell it.