I've no idea, tilly - my account is staying with Lloyds, I had a letter from them the other day, and my online banking is working fine.
If you are now TSB then I believe that you will have new sort codes etc., but they should have notified you. If you are now with Lloyds then TSB shouldn't be doing your transactions (as I understand it) - but staying with Lloyds means none of the sort codes change. You need to be sure first whether your account is now Lloyds, or TSB.