What's the model code and current software version of your TV please? Go to Home > Settings > Support > About This TV. Also, could you try a picture test for us please? Go to Home > Settings > Support > Self Diagnosis > Start Picture Test. Can you still see the purple patches?
@Lynseyburt: Thank you for clarifying that for us. Based on the results of the Picture Test I recommend reaching out to one of our Support Centres to arrange for an engineer to inspect the device. To find your nearest one please check the link below, select 'TV & AV > Television' and enter your post code. Our standard warranty runs for 12 months from the purchase date therefore, due to the age of the device, a charge will be applicable to cover the cost of the service.