I don't know if you have heard of Zoostorm (it's a British brand)? They make pre-built PC's. Well this PSU came from one of those builds. I bought it off a mate for a good price, kept the PSU, 1060 6GB etc. and sold the RAM, mobo and i5 cpu. Well anyway these Zoostorm PC's come with a 3 year warranty (if you don't break them up haha), so I presume Zoostorm specified a fairly decent PSU from FSP for these builds.
I think I will keep the FSP like you said. Also saves me from rummaging around in my PC unnecessarily.