Thanks Mathpac,
Fair play to you that link is very good and at least could check against the different SSD that are compatible. That link is very handy. I also downloaded a program called Speccy to get idea on the laptop spec which was useful as want to see if RAM needs to be upgraded. Currently have 8 GB in 1 slot so ordered another 8GB for other slot. As I was on a roll I got 1TB SSD, 8GB Ram and a SATA to USB adapter to copy current SSD to new SSD to avoid having to install new OS. Found a tool last night after I posting here called MiniTool Partition Wizard which hopefully will perform the copy.
Anyway thanks for your advice..
lonelyplanet