Upvote:3
Both the stamps say "leave to enter", meaning that you are allowed to enter the UK. They say that you can remain in the UK for up to six months from the date of the stamp below, i.e. 21 June 2022 the first time and 15 Oct 2022 the second. They are not technically "visa stamps". EU nationals do not need a visa to enter the UK.
The stamps do not give you permission to leave and re-enter - once you have left you need to get permission to enter again. (Just like you had to get permission to enter in October, even though October is less than six months after you entered in June.) So if you left in November 2022 you might or might not be re-admitted in December 2022. Each time you try to enter the immigration officer decides if you are eligible to be admitted. One of the reasons you can be refused admission is if they think you are trying to live in the UK by making repeated visits as a 'tourist'. If an immigration officer told you in October that you would not be readmitted in December then you should take that as a warning not to attempt to re-enter for a while after you have left, at least until well after December. It's not absolutely certain that you will be refused, but a refusal will make it harder for you to be admitted in the future, so don't do it.