Ok, looks like it IS available, in VERY small quantities, in the UK. So, again, there are a ton of things that could be affecting your performance. If you REALLY want to see if it's a problem with the drive, then do a CLEAN install of Windows, do not install ANY other applications except the drive testing utility like CrystalDisk mark, or AS SSD benchmark, plus the motherboard chipset, network adapter and audio drivers, and the graphics card driver, and then test it. You'll have a clean result. Or, pretty much clean. Or you could boot to one of the USB bootable Linux distributions and test it's speed there. That would be even cleaner.
Honestly, I think the drive is working totally normal.