Tac-Comms, matching the language and delivery to the moment. Politely saying "I say say would you mind awfully..." in a conversqtional drawl won't get results in a tactical situstion. You need some understanding of both the law and approved operational methodology before making such judgements.
As regards the OP, its not a barrier to prosecution per se, but it does undermine the witnesses credibility. In, say, a fight where people may be making counter-accusations about being provoked, that may be enough to bin the case off. In the case of our cyclist friend it's far from desirable but I can't see how it materially affects the actual case.
However, and it's a big however, the defence may question early doors why their client is being prosecuted for whatever they have (allegedly) done, yet the cyclist is not being knocked off for a S.4a public order offence - that would be a fair question to ask, the pplice and CPS are supposed to treat all equally without fear or favour, and unless the case is quite serious its probably best to try and avoid a scenario where they also have to caution/prosecute (eligibility for either being dependent upon their previous record and any admission) the victim in order to be able to justify prosecuting the suspect.
So the answer isn't simple - it could well go to court, but there are good reasons not to do so, and if it did there's a fair chance it would be dismissed on the first morning because the aggrieved themselves has demosntrably committed offences and is being treated more favourably by not being made to account for their own behaviour. I'm not intimately familiar with this case, and even if I wanted to be we have only one version of events, but my best guess is the police are looking at whether is reasonable and proportionate to spend respurces on the matter then the outcome is so uncertain. Unkess its something really meaty, such as a homicide, terrorism, tape, etc, it is then difficult to justify doing so.
Moral of the story - behave like a prat, gob off, swear, even thump them if you really feel the need (I don't recommend that, BTW) but if you feel so aggrieved that you want the matter to progress as far as a prosecution then you greatly undermine the chances of that actually happening, and even open yourself up to counter-allegations and even prosecution. Either don't do it, or smile sweetly for the camera as you give them the w****r sign out of camera view.
