Electronic Brake Stuck

[tex]

Hi,
Can anyone please advise me what to do about the sticking handbreak on my B6 auto estate. It refuses to release the break when the button on the dash is pressed. Eventually it does release, but it might take 6 or 7 presses on the button or 20 or 30.....or more, but it does release in the end as I said. It's just failed it's MOT because of this. Any ideas please?
Thanks in advance,
Tex