The discussion linked below is about the English version of the bill. You may be surprised to see how the actual wording varies from what people believe
mobile.twitter.com/AdamWagner1/status/1243196424445136896
Then we get to freedom of movement restrictions. This is quite a bit more detailed than, and different to, PM's statement. Big difference I spotted is there is no restriction on number of times you can do each thing lawfully. You just need a "reasonable excuse" as defined
The Scottish legislation is here
www.legislation.gov.uk/ssi/2020/103/pdfs/ssi_20200103_en.pdf
I haven't checked Ni and Wales