Do you have any advice for potential travellers?
Exchange most of your money at tbe airport. This is the easiest place to do so and probably the best rates (certainly compared to hotels in Tana). Cash machines are possible but are only really present in larger places, are often out of order or have no money and there is a maximum of around £100 you can withdraw at one time (often the machine will let you do more than one withdrawl... if there is enough money!). It's also a hassle if one person needs the cash machine as it holds up the whole trip. Similarly there are often queues at banks which can take a while to exchange. The airport currency exchange took sterling without a problem.
Meals are between 15000-25000 ariary (£4-7) each for lunch and evening meal. Drinks are £0.5-1.50 each (cold beer is available everywhere!). By the time the kitty is paid for and tips at the end along with souvenirs and extra trips probably £350 spending money is needed.
There are long journeys - this is clearly documented in the trip notes. It's the only way to see everything. On a few occasions we arrived at the hotel at dark and were leaving early the next day. For one of the internal flights it was a 3am start! There are times to relax on certain days but there is a lot of travelling too.... and some is on very bumpy roads and rather 'interesting' ferry crossings - all adding to the adventure. Most of the journey was spent in a very comfortable mini-bus and a small amount in four-wheel drive cars. For those with a bit more time it would be very easy to book a few extra nights in Ifaty at the end to spend relaxing on the beach or to do some more diving or birdwatching.
Get rid of all Ariary befire you check in to the flight home (Euros is preferred once you pass through security in the limited shops in the airport).
Have some Euro for entering the country to pay for the visa - was 27 euros.
It gets cold in Andasibe and Ranomafana in the evening so take a warm jumper.
It is generally a poor country and children will ask for sweats ("bon bon") - especially on the west side. One person had brought along some pencils, balloons and brightly coloured bangels which went down a treat with the children! They like to have their photo taken and it will amuse them for ages if you show them the picture on the screen afterwards!
There are at least three night hikes so make sure you have a torch.
Hand santiser is useful as often no soap in toilets.... 'bush' toilets may be cleaner!
As you will be staying in remote areas food options can be limited at times - usually chicken or zebu (seafood on west coast which was amazing). In larger areas pasta and other options are available. No vegetarians etc. in our group. There is a three course meal on offer for lunch and dinner but often a main meal will suffice.
It is possible to wash clothes at most hotels but save this for the places that you'll be staying in more than one night. It was fairly cheap.
It is worth taking mosquito spray - I rarely used it and wasn't bothered too much (but some others were).