It makes a lot of sense to add subtitles because like you say it seems directed towards older viewers.
Having said that it's now one of my go top channels since it appeared on Freeview and i'm only 43.
It has a nice nostalgic feel and reminds me of the good old days when all we had was 4 channels and a lot of old Black and white stuff got shown.
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MIKE: I've got it! Peter Cushing! We've got to drive a stake through his heart!
VYVYAN: Great! I'll get the car!
NEIL: I'll get a cushion.