Uneven Y Axis movement

I’ve had my XCarve for several years, but not used for about six months and just moved to a different workshop. To check it out I did a simple carve of a number of holes on a grid, and noticed that some were off on the Y Axis.

I’ve checked it is square and Z Axis is also fine. Taken off belts, cleaned everything and checked the carriage moves smoothly, adjusted the offset wheels so that they grip correctly. Then refitted belts and tensioned. I’ve also checked electrical connections are tight.

When using the control panel to jog movement the right side moves fractionally before the left.

Does anyone have any suggestions as to what else to check please?

Should I be taking all carriage wheels off and lubricating them for example?