You have to be very careful. If you want her to pay rent, she will have tenant's rights.
If you don't charge her rent on a proper footing and she contributes to the mortgage, upkeep and running of the home, (directly or indirectly, she will acquire a beneficial interest in the property so if you split up she will have a claim in the equity of the house.
Depends on whether youre living there too with her. If you are then she would be classified as a lodger and would have very few rights etc.
If you mean rent the whole house to her then she would be a tenant and have rights. In this case look round locally to see how much others charge for a similar house.
Cheers guys, I will be living there with her. She will be signing a contract written by me say she is not contributing towards the bills or the mortgage. She will also be paying me in cash so no proof of payment
You are allowed to earn around �340 a month without declaring it to the Inland Revenue. That, apparently, is an acceptable rate for a lodger to pay on the 'rent a room' strategy. You could then have a joint kitty for the food. Her only rights would be as stipulated in your Lodger's Agreement, which would presumably include a period of Notice.