Most laboratories have a final session called the marking session. It gives the wrong impression to call this a ``catch up'' session, so please don't. Its purpose is merely to provide an opportunity for marking work. Most of this will be extended deadlines from the previous session, but obviously anything that requires marking should be marked if possible. Except those with special circumstances, students should not be undertaking work during the marking session: it is too late for that. This will work smoothly as long as you have generally adhered to the rule that extended deadlines expire at the start of the session, rather than at their end.