bd-r blu-ray media disks recordable

I'm guessing in the next 2 months i will move over to a Blu Ray burner and need some advice on the media to use. The most important thing to me is the reliablity of the media, i don't want to go back to it in 3 years to find it's all gone, so my questions are what kind of media should i be...

Just now (Dec 2018) are there any Blu-Ray Recordable Disks for sale at Overclockers? It's reasonable to assume they're in stock, but I can't see them on the Web Pages. I have a particular want, because I'm writing Optical Disk Recording Software for Linux. I live in a place called Holmes Chapel...