I agree, possibly not Theresienthal, possibly still German, but I will argue, hardly an immediate post-war Czech copy of Whitefriars, (were Whitefriars making such items in the thirties?) made at Novy Bor. Whilst it is true that such fine control bubble work can be found in the Czech repertoire, the candidate factory would be Harrachov, at Novy Svet. This is where many of the controlled bubble solifleur vases, imported by the likes of Jaffe Rose, originated, and probably much dating later, from the 1960s onwards, and designed by Metelak.
It is no longer possible to ask the "Glass Castle" Museum at Liberec, otherwise known as the Glassexport A.S. collection, as it no longer exists as such, and the castle is now a very expensive hotel.
Regards,
Marcus