My neice has just eaten these berries and we were wanting to know what they were - she seems OK at the moment apart from having a viral illness anyway...
I agree it is an Hypericum species. I imagine the berries are quite tart and that she would not have eaten many. Probably harmless - "St John's Wort", a popular herbal medicine is a species of Hypericum. For peace of mind, I would contact the National Poisons Information Service in the UK - telephone 0844-8920111. Ciao BrianO