On my Vonage VOIP service, there is no additional charge for the Canary Isles. It is the same rate as Spain. I've checked this by calling hotel in Canary Isles. I suspect the charging structure on PlusNet merely reflects the BT price plan rather than the rates charged by other telecoms companies. In my case Vonage charges 2p a minute with no connection fee and there are no call quality issues.
Now Zen, but a +Net residue.
