I can tell you from personal experience that what the OP and Jeffkin said is correct. In line with clause 2a of the T&C's, what you have already is what will continue. There is no mention at all about changing to an equivalent 30 day SIMO deal and, as the OP has stated, there is no equivalent to what they have. What will not continue though are any discounts you have had for the minumum term.
At my minimum term date I was not ready to change things at that point so tried to put myself onto a thirty day sim only deal. This proved somewhat troublesome but that's another story, anyway for the short period of time between my minimum term date and when I upgraded to a SIMO deal, nothing changed in terms of price, bundle or terms and conditions.
More to the point, Vodafone probably do very well out of people who took a phone with their original bundle but fail to change it before the minimum term date. Their original bundle had an element of their payment that paid for the phone, putting someone on a SIM only deal on their minimum term date would almost certainly reduce that payment, similar to O2's Simplicity deal.
