Zenith 50 Leisure ceramic hob cooker?

My ceramic hob has a tiny crack (I think it is a crack as wont clean off and your finger nail feels it) about three quarters of an inch long over front right ring position. I have stopped using that ring incase I get liquid ingress.

Cooker is just on 3 years old and in as new condition (looked after) apart from this.

Question is can the top be replaced or repaired and would it be cost effective.

I am a retired domestic electrical engineer (mainly brown goods and computers) but never delved into a ceramic hob so believe in making enquiries first.

Many thanks for any help some kind service personnel can offer me.

Phil
April 2011