Assuming everything's on time, I'd say you're fine. The IB minimum connection time for T4S to T4 is 55 minutes. Even though it's a non-Shengen to non-Shengen connection, you will actually have to go through immigration. Then you go to T4 for the Schengen section and go all the way down to the right after clearing security and then have to clear immigration again in a mini post that only serves flights to UK and Ireland.