If your already a DL / ADI (which you must be) then get a copy of all 3 current Dive Leader written tests. Have a go at all three, if you can do those you should have no issues with passing the test. Have a look at the questions you get wrong and revise those area's.
The TIE paper is basically Dive Leader Standard, after the first few questions, I actually started enjoying mine. You will find some of the questions are actually in the PIE exam that are in the DL exam anyway.
Might be worth while having a go at the new Sports Diver tests as well, as it helps with getting a handle on the style of examining / what they are looking for.
Only thing I would add for the presentation part is don't use the slides from the Powerpoint lectures as it looks very poor, one of the guys who did his presentation used a load of the BSAC stuff and looked pretty poor.
I did mine using a flip chart and a chair to hold it up. Use practical probs, I was doing rescue management and looked at the organisation and blew a whistle to wake them up half way through. Would not do it for a work presentation, but its the BSAC way
If your going to use powerpoint, use other aids. I got a merit for the presentation, and they liked all that style of stuff.
Cheers,
Gareth.