Hi
I saw that this hasn't had any replies so I had a look on the net for you and found this...
Changing your hours of work
A change in the number of hours you work can have a large impact on your work-life balance. Sometimes, the operational needs of the company you work for may make it necessary to change the number of hours that your work. Whether you work full time or part time however, any changes your employer wants to make to your employment contract must be agreed with you.
It is possible, if you are a part-time worker and your employer insists that you work full time it could constitute indirect sex discrimination.
Here are some contact numbers if you need some advice
http://www.direct.gov.uk/en/Dl1/Directo ... /DG_172106" onclick="window.open(this.href);return false;
Good luck!