Thing is tho there is no 1 science consensus. as this covers lots of fields.
You have the medical side that have side that are only there to give a medical view, they will always air on the side of caution and less deaths.
You have the data scientists. the ones that model things out. generally they themselves dont have an "opinion", Neil Ferguson is an example. he models statistical data nothing more but does keep getting asked for opinions. there will be others that are mapping out estimated dates for hitting herd immunity with vaccine cover, so on and so forth.
You then have the Virologist side, the ones working on vaccines etc and studying the path of the virus trying to predict where it goes and risks from variants etc.
You then have the Big data science guys who correlate all this data into advice for the Gov.
the roadmap dates will have been formed from all these things put together. a key factor will have been the mapping of herd immunity.
One of the biggest issues is that the Media will on the most part be talking to the medical experts. those more likely to be airing on the side of caution.