The fillet feature is creating a new edge when I'm obviously trying to smooth it.
As you can see i have tried selected more than one edge (down to 0.5 radius) and also tried filleting one and then the other none working for me yet.
Any help would be great.
unfortunately I have tried the face fillet too i think you might be right about the surfacing and are definitely right about the unusual 'puffy' angle however I'm still studying my degree and surfacing isn't something taught here so as you can imagine I'm a little stuck
If you can reduce that puffiness in that surface (was that created as a loft?), you might get better results from the Fillet tool. Fillets can't transition along a vertex from acute to obtuse. Make all surface-to-surface angles 90° or greater and it may work. If that's a lofted feature, you can perhaps add a guide curve to relieve the puffy side and get what you need.
Good luck!
If you used the lofted feature keep in mind what Jeff mentions - also one of the most important part of using a loft and getting a nice smooth transition is you need to have the same number of sketch points in all the lofted sketches and another thing is you can use multiple sketches for you loft and if you could make a 3D sketch with a smooth transition, then you could add sketch planes and additional sketches for your loft....
Does it work with the "Face fillet" option inside the Fillet feature?
What it looks like to me is you have a slightly acute angle between the left face and the face it abuts (vertical surface looks puffy), and an obtuse angle between the right face and the fact it abuts. These things are difficult for the software to solve in one go. There are some brute-force work-arounds with surfacing tricks, but those get somewhat technical to execute. Maybe see if the option above helps out first?