
Hi
Not that difficult really.
She will pay basic rate tax (22%) on the increase in her salary, no supertax paid until £34,600.
But the basic rate tax thresholds and rates are changing on 6th April so it is difficult to say exactly now much tax and NI will have to be paid on the revised rates, and a lot will depend on her personal circumstances as the rules/rates of personal allowances and tax credits is changing as well.