@BrunoBass its OSX El Capitan
Well, @ped @ezbass I've taken the dive and and bought a years worth of CleanmyMAC, £22, worth a try! It does seem to be behaving better, not making dodgy constant HDD noises! It cleared 40.5GB of Junk, 35 threats and 3 performance issues.
Ive just bought 8GB of Apple RAM too (its only capable of accepting 16GB).