Hi Eamon, welcome to motorhomecraic.
We had exactly the same problem with our step 2 years ago, although our van is a swift sundance the step is the same fixture. Sometimes it worked, sometimes stuck out halfway, or made a wee lunge for a couple of inches, we ended up bungie roping it up while on hols until we got home from Cornwall. People suggested low battery power or maybe I had hit a kerb or it needed wd40? but as the van was still under warranty Hagans put a new step on but it was still not working. The problem was eventually traced to a circuit in the "brain" where all the fuses and electrics are. Sorry I am not very technical but that's where it was, nothing to do with the step area itself!
When this was fixed we have had no problems at all. We also discovered you can alter how you want the step to operate via a wee digital display. Originally when we locked the van and walked away the step retracted but you can have the step left out while locked, which we do & leave an old pair of size12's on it so it looks like there might be someone still on board! It still automatically retracts when you start the engine of course so I don't scythe the ankles off pedestrians!
Get the circuits in the brain checked as no amount of wd40, grease, hammers, or cursing will fix it!
Good luck mate.
John