Upgraded from 5.0-4528 Update 2 to 5.2-5592
Followed the guides on generating a serial number and MAC address and added the VID and PID for USB pen
Performed upgrade which took a couple of attempts via find.synology.com
Static IP changed to DHCP and was a bit tricky to get it to switch to static IP but once done, run smoothly now
USB drive for Crashplan now stays connected where previously it would randomly disconnect
Have applied Update 1 but not sure whether to do Update 2 and Update 3
Thanks everyone for help and advice