Some Eurovox boxes need a software download in order to be able to switch off the audio description (for the visually impaired). Since you've not mentioned which model you've got, try googling this line (including the quotation marks)
eurovox "audio description"
to look for the relevant link.
(Or, possibly better, add your model number to the search string).
I hope that you're only using your Eurovox as a Freeview box. It's a serious criminal offence to use it to obtain subscription services without payment.
Chris