Sieg SX3 - Remove control panel?

New member who recently bought a used SX3. We're really happy with the mill, and we're just learning to use it. So really basic questions form me!

The spindle DRO that came with the mill when new is inconsistent, so I've bought a replacement and need to remove the control panel to fit it.

With the four retaining screws out and the spindle lock removed, it only wiggles about with about 7mm gap at the edges and won't lift off any further - any idea what's holding it on? It feels like something's hanging on at the centre. Is there a knack or have I failed to release something?

Thanks, Chris.