So my cake was going so well until I stepped back and it looks to have sunk, and just doesn't look 'clean' 

-Looks as if the ball has a puncture! 

Any help or advice on how to clean it up? 
Would I have to make another cake or is it save-able, by just maybe re-doing the fondant? 

It's going to have a scarf wrapped around the bottom, the client has asked for this;

TIA x

Maybe try redoing the ones at the bottom? The ones on the top look great but it looks a little bumpy at the bottom. Like places where the buttercream has an air pocket or you put your finger. The scarf will cover some of it

Yes, I believe that's where the boom tier had been sinking !  
I was thinking should I take all the fondant off and re do a layer of buttercream? gain a bit of the shape back? as some of the hexagons and pentagons seem to have gotten a little squished whilst it sunk?
 

You shouldn't have to redo the cake...but I think you need to peel off the fondant and start over as it looks like the white is all one piece?  Then you put the blue pieces over it?  I just don' t know if you can smooth that out.  

Before applying fondant, your base cake must be flawless as imperfections will show through.  I'm not sure how you prepared your ball, but I always completely ice my cakes first...not just crumb coat, but completely ice, chill until cold and hard, then apply fondant.   Many people do it many different ways...that is my way.  Many people use ganache under the fondant, but I would get the customers approval first, so they are prepared for a ganache base under the fondant.   My customers want butter cream because they all peel off the fondant.   Round balls are very hard to cover.    I can only say to watch some you tubes for some pointers. 

The scarf is a great camouflage..but your bulging is above where the scarf will be. 

Good luck and let us know how it all turns out.

ddaigle  has given your GREAT advice.Also, look at the pic again, and try to place the blue pieces as shown on the cake. It iwll turn out good. Just take a deep breath, get in your mind what it should look like and go from there. I have done this in my life of decorating . Most of us have.GOOD LUCK!!

Boy, does your round Logo look great.

A[IMG]http://cakecentral.com/content/type/61/id/3084335/width/200/height/400[/IMG]

Here it it finished! Thanks for all the help! X

It looks really good!! Good job!!

AThanks guys!

So much better! You did  great job. :)