I thought the will relax parking and CC and allow everyone to drive to work
If 'everyone' or even a small percentage tries to drive into London, or any other large city, the congestion will mean that it will be quicker to walk anyway even if you live 5/10 miles away.
We need a combination of measures for it to work, because there simply won't be the capacity to socially distance on public transport.
As many people as possible to WFH to reduce demand.
Varied start and finish times so everyone isn't commuting at the same time.
And yes, the people who live shorter distances and don't need to use their cars during the working day to walk or cycle instead of using public transport or driving and gridlocking the roads, leaving those options available for those who need to drive or use public transport due to disability, travelling from site to site, long commutes etc.
We all need to do what we can and sarcastic comments of the 'I couldn't possibly walk 20 miles a day or cycle 50 miles a day' are not funny or clever.