I have never been sure about this aspect of the case. Whilst it seems that the notes are definitively connected to Ruth, I have not seen that the same can be said for the pills and alcohol which seem to have simply been found at the same time. Such finds are hardly unusual on Box Hill which, amongst other things, has long been a meeting place for bikers (not the heavy Hells Angels types but they still like a party). If the police were convinced by this evidence I would have expected them to be less focused on, for example, her friend in Sheffield. And in the absence of knowing the actual text of the notes, they could cover a whole spectrum from suicide to a simple goodbye.
I remain unconvinced by either the murder or suicide theories, but accept that all possibilities remain open, although accident seems the least likely to me - at least anywhere near Box Hill - as I am sure she would have been found..