Whether the timing was right or wrong is a moot point now IMHO.
China sounded the alarm about this virus in December / January. Unfortunately as China is regarded as a country with dubious politics, bad human rights records and a tendency to not trust or share intelligence with the West, people reacted with scepticism. My perspective is that when they changed their behaviour and reached out, it should have made an impact - it meant something so serious was going on they had no hope of suppressing it and the only way to save face on the world stage was to come clean - they are human too but from a political perspective it still wasn't a purely altruistic decision, it was also taking into account that they would become a scapegoat and suffer at the very least economic consequences, at the worst end active aggression. Their actions are a balancing act for their own people / workforce / economy and that of the rest of the world which will affect them in the future.
Our government could have started investigating and preparing at the beginning of the year. The WHO did. Other countries started to.
Our government tried the keep calm and carry on approach, which meant the population, for the most part, stiffened their upper lips and sneered at those who were more concerned.
At the very least, testing and tracing of those coming in from other countries should have been much more rigorous, because this is an unknown quantity in terms of transmission, seriousness, lack of immunity and potential for mutation. Further restricting of testing to only those sick enough to be admitted to hospital amounts to gross negligence and could have been avoided with a more coherent response - we now have no idea how many people really have it / have had it, our understanding of transmission is hampered and we are way behind on mutation study.
All big events should have been stopped way before Crufts, Cheltenham and football.
WFH should have been implemented sooner. Schools should have been closed sooner. Orders should have been placed for vital equipment much sooner.
"Most people will get it mildly" and "only those with underlying conditions are dying" were very very dangerous things to state with such optimistic certainty - every day we discover that it's vicious even if you don't get as far as ICU. People are dying in the community because this virus can take some previously healthy people down an unexpected path.
The government has given piecemeal and woolly advice sometimes contradicting WHO information - regardless of the political aspect of the organisation, they know that if they stuff up they will be first against the wall if society does go full Mad Max. Our government has only just realised this and is trying to safeguard itself.
The sudden lockdown is not just because people weren't doing "as advised", it's because the government has finally accepted that their science and the science from other sources were too drastically at odds for us to continue to be reassured.
The "We didn't realise" handwringing from some ministers is disingenuous in the extreme.
Pandemics are modelled for, exercises routinely held, corporations have vested interests in being involved in this planning and there is no excuse for the lack of ventilators, PPE or other economic contingency measures for this scenario. Other pernicious agendas may be at play but it is difficult to ask questions without being accused of conspiracy thought.
The government did not call lockdown too early I feel, but I think the real reason they did was only partly to minimise spread and NHS over-loading. The other reason was because if we had waited any longer civil unrest when we hit peak would have been widespread, and much more difficult to contain.
just some thoughts.