girl's name that sounds a bit like...

[makescakeswhenstressed]

Annabel.

ie: it needs three syllables. Quite a middle class/upper class name. Someone you'd imagine to be slightly reserved but terribly polite.

and before I get jumped on this is for a character in a story!

Lydia

Livia

Sylvia

Carlotta

4 syllables: Titanilla, Sidonia, Olympia

The list for 1988 is here but I think it's US, not UK

It's got ones like
Jennifer
Jessica (which I would have said)
Amanda
Samantha
Stephanie (that fits yor bill quite well)
Melissa
Christina
Alyssa

Patricia
Lucinda
Lucilla
Drusilla
Marissa

Juniper

Going with Amanda for sure

Jennifer

Corina

Jemima. Lucinda