Maeve and Helena are both good imo! And I absolutely adore Clementina.
Romy does sound trés joli in French. Pronunciation does matter and in English it’s just a bit… meh in my opinion.
Which makes me wonder: are you in France? edit: I’ve just reread your update and seen that you’re in the UK.
suggestions (with or without the accents. One of them is my own name. With an accent aigu, btw 😉)
Léa, Léonie, Salomé, Pénélope, Sévérine, Léopoldine/a, Céleste, Louise, Nolwenn, Séraphine/a, Eugénie, Margot, Victoire, Apolline/a, Léontine/a, Mélisande, Séréna, Cecilia, Fleur, Béatrice/Béatrix, Enora, Solenn, Maïwenn/Maiwenn, Yanna, Gwenn, Yael, Alice.