Pretty sure the employer contribution is not counted, so she could increase her AVC another 12%.
Also learned recently from a pension talk at work that the 20% is based on your total remuneration and not just base salary, so the value of health insurance paid by her employer or a bonus etc can be added to base salary to increase the amount that can be added to the pension, e.g.
Base pay 50k
Bonus 5k
Health insurance paid by employer 5k
Total 60k
Max pension contribution 20% of 60k = 12k (instead of 20k of 50k = 10k)