CyclePath - Have you tried saving the graph file after you make your changes? If you do not, the next time it loads, it will lose your changes.
File - > Save SNMP Graph...
Sorry got absorbed into a major server outage over last few days. Just tried your suggestion and I'm very pleased but rather embarassed to say it worked. : )
Thank you very much. - For some reason I'd assumed it was an instant save kinda app a bit like making registry changes. - Silly me !