There are always lots of places that open their gates for you to see the snowdrops in their grounds. I have found other places to visit where snowdrops abound, these are mainly churchyards.
Shipton Churchyard (location on OpenStreetMap)
Hopesay Churchyard (location on OpenStreetMap)
Kerry Churchyard (location on OpenStreetMap)
Stanton Lacy Churchyard but not on their designated open day (location on OpenStreetMap)
The photograph used in the header of this blog post shows a carpet of snowdrops at Stanton Lacy churchyard.
The photograph below shows snowdrops at Stanton Lacy Churchyard.