I recently bought a couple of new cases for my Discovery (same as 75) due to the original, 16 year old buttons disintegrating.
Not sure how to attach a link via my phone, but the ebay ref. was 162892520725.
If you look at this, then go to the sellers other items, he has a version for a 75 which doesn't have the 'Land Rover' logo on the button. Seller was very helpful, quick delivery and the product seems good - been using one now for a couple of weeks with no problems