I've had another thought about why the police were so clear in their assertion that this was a case of someone accidentally slipping into the water. This may have been mentioned but I'm not reading the whole thread.
Please note the following paragraph is not a speculation on the current case it is a more wide remark on the consequences of how things are presented in the media.
It's commonly accepted now that the reporting of events leads to "copycat" events. News reports usually don't mention suicide methods these days because this leads to more people attempting suicide by that method. News reports of shootings are more carefully worded because studies have shown that when there is a mass shooting covered in detail on the news there is a much higher chance of a similar attack in the near future. I was looking at the Raoul Moat case last night and it's likely a factor in his behaviour was the coverage of the Derek Bird attacks a few weeks earlier. A study in the US concluded that when there is extensive nationwide coverage of a mass shooting in the news, there's typically another within a couple of weeks.
Therefore, whatever the police's view on what the circumstances are in this case, we have to consider whether they are telling us something because it's true, or because it seems the most appropriate thing to say to help this case be resolved quickly and nobody else be harmed. Just because they say they're solely focused on one outcome doesn't mean they are not investigating other possibilities. We shouldn't take what the police say as 100% accurate because they may have a motive for lying in order to get the best outcome.
IF there was foul play at work in a case, media coverage and celebrity might be the very thing the suspect was after. If granted this coverage they might do something else. Likewise, if someone chose to disappear because of mental health struggles, a massive manhunt might not be the safest thing if they pose no risk to others and just need some breathing space.
To piece together a story, it's important to understand why someone says what they say. With the police we don't know what their motives are, so relying on a police statement at face value is not a reliable way to get to the truth.