Paint Refurb

That product actually describes itself as 'non-abrasive' so perhaps test it on a less critical area, under the BB shell for example.
I doubt there will be any chemicals in a Meguiar's polish that will react badly with your paint.

I was told that polishing could damage the clear coat of the original paintwork

That's precisely how most proper car polish works. It finely scratches through dull flattened clearcoat to reveal a pristine layer beneath. Different grades of polish will have more or less aggressive 'cutting' power. It's very easy to apply too much pressure or use too coarse a polish and burn through the clearcoat to the paint, particularly on non-flat surfaces such as bicycle frame tubes.