If you look at your latest Orange bill, they are going to be charging for numbers like 07978 that are used to call abroad from December 15th. However, there is a clause in the Orange contract which enables you to terminate the contract early.
it is clause 4.3 in that link, the clause is:
"4.3 terminating your Contract because Orange has changed its terms
You may also terminate your Contract if we vary its terms, resulting in an excessive increase in the Charges or changes that alter your rights under this Contract to your detriment. In such cases you would need to give us at least 14 days written notice prior to your Billing Date (and within one month of us telling you about the changes). "
So if you want to cancel your contract early because of these changes, do it quickly but avoid paying for the remainder of your contract when Orange no longer give you any benefit!