Thank you!I have done this route a few times in the past, probably 3 or 4 times. Generally towards the end of October, although I did also do the DE part in August 24.
As mentioned above the reefs on these off shore sites are still pretty good. I think on my dives at Daedalus I have seen hammerheads on about 50% of them. Expect a hammerhead or two, you won't see schooling hammerheads. Oceanic manta also now seem to be an occasional vistior. I have seen a couple of these on different trips in October. For the first dive of the day at Daedalus the normal format is to drop into the blue and hang out to see what is there, max depth is up to you - the viz will be very good so you can be at 20m-30m and easily see a guide at 40m. There won't be any pressure to go deep, but you will need to keep eyes on the guide. Normally I let the guides go deep, and then only descend if they spot something interesting. While most people will dive nitrox during the week, for the first dive of the day there is normally the option to have an air fill, so you end up with a weak nitrox mix for dive 1. Depending on what happens in the blue, and the current, it will either be a blue water ascent, or a drift along the reef wall and ascent along the reef. If you are unlucky you can spend the dive just looking at blue water, but you do have a good chance of something interesting appearing. The 2nd and 3rd dives of the day can vary depending on what was seen on the first dive. Normally the 3rd dive is a drift along the reef wall.
For the BDE route expect the first and last dives of the trip to be a bit underwhelming, once you get to the actual BDE part the diving improves. Sea conditions can be a bit rough in October, , so expect a rough over night crossing at some point during the week - it is unlikely that all night crossings will be rough. Depending on sea conditions some of the zodiac rides to the drop off points can be exciting! Equally I have been there in totally flat conditions at that time of year.
If you done this a lot in October, what did you usually see apart from the hammerheads and manta?
Some thresher, oceanic white tip sharks, dolphins maybe?