With regard to younger people, it's a more difficult story regarding how sick they may or may not get. There is certainly an argument that blood clotting risk starts to outweigh Covid risk with certain vaccines.
However, we need the young to vaccinate in order to reduce the risk of a particularly virulent strain, and to reduce the spread.
Sadly, this is a global issue, and keeping the UK in good shape is ultimately 'p....ing in the wind' if the entire world can't get on top of things.
I can see how particularly wary people are unsure about vaccines, and with the blood clotting issue, that only serves to heighten their fears, however improbable (statistically) it may be.
Ultimately, as a population, the more people get vaccinated, the less deaths, and conversely, the less people get vaccinated, the more deaths.
To say 'My choice not to get vaccinated, doesn't affect anybody else' is ultimately not true. Yes, it's a personal choice. Yes, nobody should be forced. We all make choices in life that affect others, sometimes disastrously, but at least acknowledge the choice being made, rather than claim it has zero bearing.
I don't think people should be castigated for making such a choice though. After all, we were all happy to get the vaccine ahead of others in the world when arguably others needed it more than us. That cost lives too.