I want to give up my mothers landline that she's had for years but no longer requires as she's moving elsewhere. Is there any chance I can get some kind of call forwarding to another number as she (oh and me!) has relatives that might only use this number once a year still and I may have forgotten to give them a new number to contact her ?
No, if you drop the service then Eircom with make the number inactive and they will eventually give it to a new customer. You cannot forward from a number that has been de-activated !