You can work your ass off, do retakes next year, and hope to god that you get A's.
OR
You can resit the year, you will almost definitely get the A's you want.
Option one means you won't get offers to higher up unis because of your predicted grades, but you don't do an extra year.
Option 2 means oxbridge and RG unis might not want you because you've resat, but you get the grades you want, and still get a place in a decent uni.