Don't give up. The ABRSM exam is scored based on different elements of the test. You know which part(s) of the test you are lacking in. Work on those, while maintaining or improving the other elements.
If you do not understand the examiner, just politely ask him or her to repeat, or say it again. They are well-trained, and they know there are possible language problems. When you do not ask or respond, then they would assume that you understand what is being said. Prepare well, and you will be fine. You had done well before in your Grade 7.