As per OP's original comments, can't find anything in the international link provided that specifically mentions channel islands nor in any other VM doc's which mention additional charges for the channel islands
Jersey code appears to be 01534 and Guernsey 01481 and are listed as +44 UK numbers
Talk More Anytime plan in the 'Everyday Call Charges' doc says geographic numbers starting 01, 02, 03 are included in Talk More Anytime.
Further clarification would be helpful.