made me think of one or two British post war modernist designers - but having looked through the books probably not - the U.K. seems to have used this cross-hatching only very rarely, so my opinion more likely to be Czechslovakian. Reasonably quality, with ground/polished rim, bevelled inside and out - ditto with the pontil depression, and a good refractive bright glass if possibly a little too acid polished on the cutting. Nearly a centimetre thick in most areas - unfortunately, no mark that I can see - and remarkably free of cloudiness for a vase, although some base wear. Height is about 7" - 180mm.
Pic 2 is taken through the centre of one flower, and looking at the flower on the other side.
Would be interested to hear if anyone agrees with my suggestion of Czech, and any thoughts on a possibly factory - thanks for looking.