Niamh Fairbrother

Niamh Fairbrother was one of the twin daughters of Barry Fairbrother. As she was in the same school year as Andrew, Fats, Krystal and so on, she was presumably about the same age. Andrew described her as the "less pretty" of the twins, implying that the twins were fraternal rather than identical.

Etymology
Niamh (approximate English phonetic spelling "Neev-uh") is a Gaelic name meaning "bright" or "radiant". It is thus a cognate of "Roberta", and probably of other English names.