Try to listen to some real French every day from now until the exam. You don't need to understand every word, but listening to French spoken as it is in the country will make the GCSE recordings sound so much slower and easier to understand! It only needs to be 5 minutes per day, but you need to pay attention and pick out the words that you can, even if in the whole thing you only understand 'bonjour', 'monsieur' and 'francais'! You can also watch French TV (perhaps 'Extra French' on youtube, or there are some programs on netfilx).