That "Vital Spark" was formerley known as the Eilean Eisdeal, she is a diesel powered VIC (Victualling Inshore Craft) and wasn't the vessel used in any of the filming of the Para Handy series, the actual vessel used was the Auld Reekie now undergoing restoration at Crinan after languishing there rusting away for many a year.
The "Vital Spark" nane was never on the Ships Register, and when the owner of the Eilean Eisdeal realised that fact was quick to register the name to his vessel, in recognition of the fact that the author of "The Tales of Para Handy" a certain Mr Neil Munro was born in the town of Inveraray.

Chris, you should have called into the tourist Info Office whilst in Inveraray and had a chat with me.

Chris