L1 Numerical test and L2 literacy tests before the interview. What should I expect?

Nothing too difficult Busy Bee. They just want to ensure you can do basic Arithmatic and string a readable paragraph together. The wording of your question would indicate that you will not find L2 Literacy too difficult. If when you go shopping you have a fairly close idea of what the bill will be before the cash register tells you then L1 numeracy will not worry you either. We did both these in the organisation i work for and my own impression was that a half way intelligent 12 year old could probably p them!