Are you sure that the Pearl guys lost their long service leave entitlements when RFDS took over?
Taking over a contract is not taking over a business, the new company slides in and pushes the old company out. The existing staff
may be offered transitional positions but on new contracts in a new workplace. The company they work for would be required to pay out any existing entitlements as severance pay when they leave, that is if the existing company remains viable and does not slip into insolvency, then the staff get what they can. Pearl would owe entitlements to the workers, however the RFDS would owe them nothing until the start of contract date, at which time everything resets, unless of course part of the tender included a continuance of existing entitlements.