After trying a number of others it seemed that all needed a slider image size specified in the module and remained fixed and static ie didn't scale with fluid layout.
Viewed Vinaora demo and found that it did! Installed and out of the box did exactly that.
As far as can see the px sizes in module are max width and height and the images scale to fit the css specified sizes ie 100%.
Will be using this one for all new sites now; no need to look any further.
Easy install, easy setup; just supply folder, max image sizes, transition, that's it.