Thank you for looking Mike
The only way I can see to check them is by checking the enamelling on the various signed pieces against the unsigned ones. I've searched these for a long time and I see the same or similar pieces being attributed to Harrach, Moser, August Jean, Leveille etc with no real evidence to support the attributions... for example there is a vase I see that is variously attributed to three of the above makers but I actually think it is a Baccarat vase based on the colour and the enamelling and comparing to a piece in Cappa - I never see it id'd as Baccarat.
For my vase, I think without a signature it's going to be very difficult to find out exactly who made it. It makes it harder because it has no further applications (apart from the plain feet) and no enamelling to compare to signed pieces either, but I have found an undecorated version (see below).
With regards dating it I found a plain drip rim non decorated Leveille vase in the Musee D'Orsay collection - it's not the same and the only similarities are the drip rim and the use of clear and turquoise glass - it doesn't have a pulled rim, the drip is turquoise on a clear body, so the other way round to my vase, it's a rounded shape and the foot is a circular applied foot rather than individual feet.... but it dates apparently to 1875-1878, so it wouldn't be unreasonable to assume my vases dates to about that period I think.
Thanks again to you and Ivo for all your thoughts and help which is much appreciated