1. Would a skimmer be required in a tank of this size or is that more
dependant on stocking levels ? If so, will a Aqua-Medic Miniflotor
Skimmer be man enough - quoted for use upto a 200 litre tank !!

Each Skimmer is rated for the tank, make sure yours is the right Tank size
ie Some say up to 75 gal or something similar

2. Do I need a steriliser ?

No. You don't want to kill the good bacteria

3 Would a sump setup be a better option right from the word go ?
IMHO it's a matter of preference. If you want to hide your filters / heaters
then do it. If you're is like mine, with the filter hiddne behind a wall,
then I dont see why you would want it

4. Are they any downfalls or issues in using this type of setup /
filtration that I should be aware of ?

Yes Nitrate build up, I would use a canister without Bio Media, the Live
rock with act as a bio (After your tank cycles) and will help your Nitrate
stay low

When you set up the tank, you should use a deep sand bed for the substrate
( about 4 inches), unlike a fresh water tank, when you do your partials, you
try not to disturb the sand. You can place the LR ontop of the sand, let the
tank cycle before adding any fish ( Make sure ammonia and Nitrites are zero)
This make take a few weeks. During this time, get yourself a good reef book
and read it, then get another and read that. You don't need corals right
away, it sounds like you want a Fish only with Live rock (FOWLR) Lighting is
not as important as its when you add corals. as far as fish buying if you
are using RODI make sure your local fish store is also using RODI if they
are not, go someplace else. This link is a useful guide for New Tanks
owners for compatibility
http://www.liveaquaria.com/general/c...lity_chart.cfm

When you get stuck you can post ur problem here, and wait for a response,,
you're looking for the most consistant asnwers ( everyone has a differnt
opinion on how to do things in here)
Good luck