I like [name_f]Olive[/name_f] [name_f]Frances[/name_f], but I do understand the hesitancy with how popular it is in your area. How about:
[name_f]Pippa[/name_f]
[name_f]Poppy[/name_f]
[name_f]Della[/name_f]
[name_f]Blythe[/name_f]
[name_f]Effie[/name_f]
[name_f]Etta[/name_f]
[name_f]Nell[/name_f]
I absolutely love [name_f]Cora[/name_f] & [name_f]Olive[/name_f] together! [name_f]Olive[/name_f] [name_f]Frances[/name_f] is such a pretty name I think you may regret using [name_f]Olive[/name_f]. Personally I haven’t met anyone called [name_f]Olive[/name_f]. I’m also a fan of [name_f]Maeve[/name_f] & [name_f]Maud[/name_f] but [name_f]Prudence[/name_f] isn’t my thing.
You’ve had a few suggestions so count any repeats as me being in agreement with the berries
[name_f]Cora[/name_f] and…
[name_f]Effie[/name_f]
[name_f]Joy[/name_f]
[name_f]Delphi[/name_f]
[name_u]Noor[/name_u]
[name_f]Opal[/name_f]
[name_f]Iris[/name_f]
[name_f]Goldie[/name_f]
[name_f]Sylvie[/name_f]
[name_f]Elsie[/name_f]
[name_f]Enid[/name_f]
[name_f]Tess[/name_f]
[name_f]May[/name_f]
[name_f]Anouk[/name_f]
I love [name_f]Gwen[/name_f]. Though I can’t decide if in the in the UK it reads to Welsh? And it is better with the long form [name_f]Gwyneth[/name_f] or [name_f]Gwendolyn[/name_f]? Definitely a maybe. 
[name_f]Enid[/name_f] is our cat!
[name_f]My[/name_f] first thought was [name_u]Hazel[/name_u]. Other ideas:
[name_u]June[/name_u]
[name_f]Mabel[/name_f]
[name_f]Ruth[/name_f]
[name_u]Louise[/name_u]
[name_f]Josephine[/name_f]
[name_f]Adele[/name_f]
[name_f]Ada[/name_f]
[name_f]Rose[/name_f]
[name_f]Verity[/name_f]