Thanks Maggi but we have had ample 'normal' bright red fruit for many years and this is the first time we have seen this effect.
One of the white 'fruits' I found had had a quite normal looking skin on it but it has almost entirely fallen away now, and so I tried stripping one of the normal fruits. Lo and behold, the unripe seeds inside are what we have seen. Problem solved,
On the other hand, WHY have the skins fallen off?
J.