Immigration can be complicated and expensive. A brief overview might help:
To enter the country she needs 'leave to enter' and to remain in the country she needs 'leave to remain'. In plain English, that's covered by a spouse visa.
The partner would need to apply for a spouse visa (form VAF4A if she applies outside the UK). The granting of this visa would give her the ability to enter and leave the country and allow her to stay for up to 33 months.
With a spouse visa she should be free to work in this country without an additional work permit.
She would have to demonstrate that she would either be supported by her husband or could support herself for the length of her stay.
She should be free to work in this country without an additional work permit. She would not have access to public funds (welfare benefits, etc).
She would have access to free NHS treatment.
Hope that helps. Citizens Advice should be able to give you more detailed advice.