I volunteered to help with the costume sewing. At first we just went through heaps of fabric to find suitable cape material for use in outdoor scenes.
Then I was handed several yards of brocade and Butterick 3648 (out of print, sadly) to make Scrooge's dressing gown. The pattern wasn't actually quite right for the job -- the skirt was too wide, the front edges had no facing, it had no belt. But it was much closer to an appropriate shape than any current patterns by the major companies.
So, after reducing the skirt width by folding up the pattern pieces, making facings for the front,
making a belt (sewn directly to the robe) and adding a pocket
Scrooge had a rather nice dressing gown
which was his costume for most of the show.