ED9 CRX Power-steering Troubleshooting

I seem to have an issue with the power steering.

The '88 CRX is an ED9 with a B16A and has just had the CV boots and Power-steering boots replaced, and Hubs tightened - which leads me to suspect something might have been inadvertently done that has caused this issue.

The power-steering seems like it is working most of the time, though occasionally - usually turning left, it becomes very difficult.

The power-steering fluid level is fine, and my next port of call will be to check the tension of the PS belt.

Does anyone have other suggestions on where to continue troubleshooting this?