I would make a significant change, which would help a lot of people and might encourage people not to travel to work if they don't need to.
It should be noted that it would also remove the need for a lot of things to be in place, and so wouldn't be as costly as it would first appear.
I'd bring in universal basic income at a value of £7,000 which would be tax free however this would remove work based benefits, other tax free allowances, child benefits, and other things like that.
To pay for it there would be a flat rate tax of something like 40.1% meaning that those earning over about £27,000 would start to pay more tax than at present.
Those earning more would pay more tax, so someone on £49,000 would be paying £3,400 more tax (even allowing for the £7,000), however it could be that as a household they are no worse off. Whilst tax payed would continue to rise it wouldn't rise very fast much beyond this because of the current 40% threshold. However to provide time to adjust any person could defer 40%, 30% and 15% of the extra tax owed in the first, second and third years to be paid back over the following 20 years or upon death whichever is sooner (basically for the above example reduces the tax by a total of £2,000 to be paid back at £100/ year)
It would cut a lot of red tape from the government, with no self assessments for high rate tax payers, which could save the state a lot of money. State pensions could be reduced, as the UBI would already be more than it anyway.
There'd be less arguments about if we needed to provide free school meals during school holidays as there should be suitable income for that.
It would boost the economy in areas with low salaries and therefore encourage businesses to employ more people in those areas.
Minimum wage would remain, but would have to be addition to the UBI. Given that it would remove some benefits there wouldn't be the same sort of limits in place to stop people working more than 15 hours a week before they lost their benefits. However to stop people benefiting too much by going onto benefits before coming off them there would be a benefits tax of +14.9% on earnings of those claiming benefits (so that they are paying 55% tax on their earnings, so for every £1 earned they loose 15p in benefits but the government gets 55p, so that it's worth everyone's while working more).
How's this linked to Covid? Well it would replace the need for a lot of the support packages and allow those not to work if they have symptoms.
This should encourage people to follow lockdown rules more easily without feeling that they are going to put their finances at risk.
It would mean that there's less people missed in the support deals and could allow people to "keep" their jobs whilst the economy picks back up again and companies to start to pay them again.
I'd also bring in a rule that states that companies can only limit their staff from working for a competitor where they are earning more than double minimum wage or they are employed for a total of 37 hours a week. They could stop any other employment if they are the employer providing the most hours and it would mean that member of staff working more than 60 hours a week on minimum wage, this would be linked to rates of pay so for each 5% above minimum wage it would reduce the hours by 1 hour, so someone on double the minimum wage could still work up to 40 hours across two jobs without their being a limit imposed on them.
The other Covid-19 rule that I'd change is to bring in the 6*6 rule. Basically the rule of 6 but to be limited to 6 groups each month (work or school counts as one). However you can have one of those groups to be another group of 6 (with a 2 week gap between each different group) which you can meet with (so families can meet grandparents or cousins). However it would limit the total number of people that there's interactions between.