yes, I need a bit of time to look up the information and for someone else to double check it
I think it's important you find out the correct maker - that could lead to more information on the person who worked on the piece, or at least a 'name' of where it might have been decorated.
I will come back to you later with any more info. I'm sure this type of pattern was done by Stevens and Williams (I don't know about Webb as haven't looked up anything about them).
You could in the meantime google 'Stevens Williams Dolce Relievo' and 'Stevens Williams cameo glass' and see if you can find any more information. Also check the Corning Museum of Glass and the Victoria and Albert Museum site as well as a site called Gorgeous Glass from Broadfield House Glass Museum.
Leave out the 'and' in the middle of Stevens and Williams and just use Stevens Williams ....