Had the guys from The Grid come around a few months ago when I had my second EV charger fitted. Why it takes two of them to come around but then their office is only a mile away. They downgraded my main fuses from 100A to 80A. Someone on here said it is now Grid policy to do this as UK houses, maybe especially here in the Midlands due to the temperatures we are getting ie 35C, that the house ring main etc are getting too hot due to the higher ambient temperatures and homes are running more power in the summer than they use to when it was mainly winter that the electrical load was usually higher. In practical terms it is no issue. Even with an 80A fuse the load would have to be north of 100A for more than 4 hours, see National Grid document attached. Most I tend to see is around 15 kWs, voltage can between 220v and 240v of course. One of my EV chargers is only 3.6 KW, the other is 7.2 KWs and I can be charging home batteries with 2KWs an immersion heated with about 4 KWs and sometimes tumble drying but rarely at the same time and I have my Octopus Mini to tell me live power consumption and give me an idea of how much I am saving when I am running multiple heavy loads in my 5 hours of 8.5p per KW/hour. Be a same to miss out of super cheap home charging and car running costs. Our lecky bill is currently under £75 a month, gas less than £25 so paying £133 a month, 4 bedroom house, 3 EVs we are building up credit for the winter and with gas at 5.71p per KWH and the cheap 5 hours of lecky, I have a couple of solar arrays that track the sun, when there is some, and with the home batteries, lecky in the day is almost nothing. 80A or 100A is nominal, these "fuses" will run much more that without blowing for long periods as the graph on the attached shows.
Standardisation to 80A.pdf