colossus 131 cryptic

51. Across penny with unusually simple indentations, ?i???e? DIMPLES (an old penny = d)
52. Down.Rather horrible scene from Favourites, ??e???en?e? PREFERENCES (rather = "prefer" + anagram of "scene")
65.Across. A most pure production followed the long running play, m?u?????p MOUSETRAP (Agatha Christie play still running after approx. ten million years)
47.Down.Sly USSR people wandered aimlessly p?r???????s?y PURPOSELESSLY (anagram of first three words)

Thanks Imur, appreciated. I couldn't get my head around that lot. Makes sense when you see the answer. Cheers, Barby.