Unfortunately, it's the time of year when Morgan workshops are around their busiest, with those who park their cars up for the winter discovering things that need rejuvenating because the car hasn't been used for months.
Williams do occasionally slip up on responding and as Peter said they are very short staffed at present, with some being away. You could try New Elms (near Shaftesbury) but I suspect they are just as busy, or Millers (High Wycombe) who probably have the same lead time too. TEchniques may be another possiblility, but they're in Hertfordshire.