The Interview Questions are Formulaic and require a Three-Stage answer.
[What happened, What you did to effect the outcome and what that outcome was]
For f"@%S Sake don't witter on. Treat it like a Transatlantic Position Report.
The Maths; all I can say is if you can do manual loadsheets without the use of a calculator inside of a minute you'll be in the zone.
Keep Hydrated (Brain Function directly proportianal to...) and remember to get some sustainence on board at some point. Probably not during "Lunch" as you'll look like a right Plank eating your Jam sarnies while everyone else is Networking.
I did both English "A" Levels and an Essay-based Degree and still found the Verbal Interpretation the hardest part. Just forget what you already know and treat each passage on its individual merits.
I just came in to wish you all good luck. Good Luck.