I would guess that the colour used will be a pantone colour as these colours are, apparently, frequently used for packaging.
Have a look at the colour chart here https://www.pantone-colours.com/ but remember that what you see on screen may not be as true as it could be. Maybe try asking Hornby?
PS Box colours fade a lot in sunlight. There was a Hornby box in a local shop window that was a very pale pink colour