I've said that many companies are going to be remembered for their actions during the pandemic - some will be remembered for doing the right thing, others will be remembered for not offering the same, or making life more difficult.
It makes perfect sense that insurance rebates should happen. I was put into government 12 week lock-down and during that time I've completed about 12 miles a week.
However, I'm with GA, part of Aviva group by looks and nothing - in fact one of their FAQ's said "What if I find I'm currently doing less mileage" to which the answer was "You can make is aware, however it will make no difference to your premiums".