The problem is thus:
In the Designer I see this… (Good)

In the JSP viewer (built in CR4E Crystal reports for Eclipse) I see tis (Bad)

The main issue being the scale on the x axis where 0.04 has been rounded down to 0 and 0.08 has been rounded up to 0.1.
I have tried modifying the reports by right-clicking the label and clicking “Format Axis Label” -> Number and specifying decimal places there but the rounding is unchanged.
Any ideas?
In the end I sussed out a workaround, and also an error I made. When choosing format axis label I was doing so in print preview, which didn’t carry through to the final reports. My fix has been to do this on the proper design view.
The worry I have however is that if all charts require my intervention in this manner when they look fine in print preview then there must surely be some kind of problem with the java renderer.