MCSC roof wear marks - Ext. warranty only covers 50%?!

[Pops]

My 05 MCSC is showing 4 marks on the roof where the fabric has worn away, I guess from resting on something sharp when the roof is down.
My garage took pictures and sent this to BMW for a warranty claim under the extended warranty, however, they have offered to only pay 50% of the part cost and none of the labour.
Anyone else had a similar problem and can give some advise on how to get BMW to accept this a warranty claim?
Surely a 5 year old roof should not be doing this.

Thanks!

[RKDE]

I have never seen it, got 2 of them in the family and no problems and its not a common thing, 50% is good as mini wont even accept it a fault when you wind the front windows down and the back one blows out (only some convertibles but it happens). They only offer part the cost to a steering pump which are very much known to be a problem