Long Haul charters usually have a couple of hours on the ground before their next flight. The flight is only 4 hours late so will hopefully make up time within the next day or 2. Looking at the SFB website it has knocked onto tha GLA-SFB flight which is due to depart at 1430. If the a/c landed in MAN at 1300, it will probably only leave GLA an hour or 2 late.
Things in this industry change so quickly, it would be impossible to predict how your flight will be 2 weeks in advance.