I collect Whitefriars, Liskeard and Beranek knobby vases. I do love my knobbys lol.

It does look similar to my Czech Skrdlovice Jan Beranek large piece that I have in green BUT every one of his vases are different. It is the same as the Liskeard ones I have. Which this vases is definitely not Whitefriars or Liskeard.
For all three makers there are lots of size, weight and look differences but are all by same maker. I also have a smaller one by Jan in red, again if I do an eBay search the ones in red are all different. Some the red goes all the way to the bottom, others there is more clear glass appearance near the base.
I would say that your thoughts are most likely correct and it is a Jan piece. I would take a look at eBay to see what I mean.
Nice find, happy hunting

Meachelle