What happens if i get 1 grade above my conditions and 1 below?

I think that depends on the course and how in demand it is. You would not have met the conditions of the offer but if there are spaces on the course after they have sent out all the confirmations then they could still confirm the place for you too, as a very solid near miss.
If not, then it goes to your insurance choice, which you should get because the grade offer would be lower

Firstly, please don't multi-post exactly the same questions on different forums.

For ALL courses at all Unis, there are usually a few spaces once they have accepted those who have met their offer conditions. Then they will look at 'near miss' applicants to fill any spaces - and each Uni will have a different process and agenda for this so there is no point in guessing it.

Just make sure you have a sensible, lower grade, Insurance choice that you actually want to go to.

And get revising - ie. how badly do you want Leeds.