Cheers royaltiger.
I have just phoned up and taken advantage of that offer. I was paying Vodafone £5 a month on my existing phone contract for their Vodafone Family add on, where you can phone 3 other Vodafone numbers for free. Me and the misses are going to both move to this tariff (her contract is up with Vodafone soon). She'll be saving £10 a month and me £5 a month, and we still get unlimited calls between the two of us.
Nice work VM