The nature of the Glasshouse and the composition of its members was such that there was no recognisable Glasshouse style, just a number of disparate styles.
I think these were designed by Annette Meech but they could equally have been designed by Christopher Williams or it might have been a collaboration between them.
So the only way one would know that this is a Glasshouse weight, is by experience and having seen or handled one before.
What does make it interesting, is that while many people at this time were using stannous chloride to irridise the outside surface of their work, it is quite unusual to see it used within the glass like this. It gives a similar appearance to the effect gained by using dichroic glass inclusions. http://www.sivignonglass.com/index.php3?langue=en
this is where you will find them now. They will be able to tell you everything you need to know!
If you are interested in the Glasshouse there is an excellent exhibition on at Contemporary Applied Arts http://www.caa.org.uk/