I’v found a couple of photos of the trailer showing the old and new axle. No wonder there’s a problem, the new axle is about 9 inches ahead of the old one.
Here’s the picture of the trailer as originally supplied:
As you can see, the wheel centre is at least 9 inches behind the sixth upright post between the top and bottom rails of the trailer.
Whereas, the new axle is fitted to the trailer with the wheel centre
about level with the sixth upright (it’s hidden behind the wheel).
Considering that the axles were changed by the trailer manufacturer, you’d think they would know where to position it!
I suspect I’ll have to shift the axles further towards the rear.
I suppose I could move the winch post forward and thus move Riff Raff further onto the trailer……..