Yeah, the battery management system keeps an eye on things. And I/the software 'balances the battery' every month so all the chemicals are put back in the right place (hard core tech explanation!).
As MfH says, I fast charge all the time and am losing about 1% battery a year. In practical terms, that means that after 5 years, my MG5 will go ~300km instead of the original ~350km. Since I almost never do more than 150km per shift, I should be alright.