I saw this advertised some time ago and thought I must get some for Christmas. And now I can’t remember its name. It was described as being ‘sherbety and lemony with a champagne fizz’. It was called IIRC Gemma di Something-or-Ever
Google ain’t helped.Can you?
The only wine I know called “Gemma” something is a Masciarelli-produced plummy red called Villa Gemma, and that doesn’t seem to quite fit your description 
“Lemony” to me suggests a cava, but other than that I can’t help.
Or can I?
Moscato del Piemonte Gemma. “Like sucking a tube of refreshers - a gorgeous, light, semi-fizzy medium-sweet white.” Cheap and cheerful, and said to be good with Xmas pud…
That’s her
Thanks Colophon.I shall go get my bottle for Christmas to accompany my Bucks’Fizz and Babycham.