I don't know the MOL for the different storage classes, but it is almost certainly a very low figure. The maximum extraction rate from (long and medium range) storage probably drops off as the storage level and therefore pressure falls toward zero.

The national pipeline infrastructure also has a minimum operating pressure. In the winter months, the operating pressure is raised, so that gives a little extra leeway as the extra gas in the pipes can be consumed before MOL is reached.

Not mentioned in this thread is the supply from the UK LNG terminals. Without LNG imports, the UK would have already run short of gas this winter. LNG is expensive, and the supply even more of an open market, but the LNG regasification terminals themselves can act as short term gas storage if they have a delivery at the critical time.

With respect to LNG I don’t have actual data available yet, but as of now I would expect LNG to be up by approximately 5 Mcm/d since early January.