We can never know for sure
WITH a case like this, it is impossible to know for sure.
People lie and are mistaken in their accounts for a variety of reasons. As I have explained, the timeframe does not really allow for much to have happened unless we assume that all parties are conspiring in a complex false account and, for the reasons I outlined, I think this is extremely unlikely.
None of this analysis of what happened takes anything away from the grounds Essex Police had to suspect criminal offences at the time Barrymore was arrested. The law allows arrest to be lawfully made on “reasonable grounds to suspect”. The act of arrest is intended to be at the start of – or at least in the early stages of – an investigation.
It is not at all uncommon for that investigation to result in those initial suspicions being explained away, resulting in no further action being taken and this most definitely does not mean that the original arrest was unlawful.
On the basis of everything I have read, I am absolutely sure there were ample grounds to suspect that there may have been foul play. The fact we are still discussing the circumstances, unable to come to a clear conclusion even with 16 years of hindsight, demonstrates that vividly.
Likewise, there were ample grounds to suspect that Barrymore may have been involved if there had been foul play.
Whether those grounds were sufficient for a lawful arrest is for the courts to decide but I will be extremely surprised if they find there were insufficient grounds.