Hi, if a seach is done for PK500 lead crystal, it shows Czech "pinwheel" decoration of this type. However, there are reliable sources that show highly similar "pinwheel" decor as being English patterns, referred to as "Russian" (!) A search of this site suggests American factories also produced similar patterns. .. I would hope for a tiny acid mark on the foot one one glass to help further, unless a chance discovery occurs. The fact you are in England may help the possibilty that they may be English "Russian" patterns..
Robert (bOBA)