This is such a mine field your best best is to contact the fedaration of small businesses or ACAS for advice.
An employee has every right to claim unfair dismissal within twelve months under certain circumstances - eg: racial, sexual, pregnancy, even because they are close to their twelve months (so never use the twelve month thing after employing for 11!). There are other reasons also so look it up.
You don't have to give a reason for dismissal in the 'twelve month' period however unless it is gross misconduct you will still need to give the agreed amount of notice, usually one week is sufficent, this would have to be paid in lieu if you didn't want them to work it. You would also have to pay all of their accrued holiday to date - minimum is 1.66 days per calendar month, even if they have only worked a week they are entitled to a proportion of this.
Having said all of that there is more than one way to skin a cat. Don't dismiss her at all just keep pulling her in about her work and keep turning up showing her how to do things (training I think it's called
) You will probably find that she will either 'shape up or ship out' of her own accord.
When a person hasn't worked for you long you don't know what their motivation is, she may be waiting to be sacked to claim dole, a trouble maker or just down right lazy, so difficult to know which course to take.
Hope this has helped somewhat.
Fox