It would be more compelling if it actually included some numbers. What is the average salary for ground staff, what proportion of employees are actually on zero hours contracts, how do salary levels compare with other employers in the Luton area, for instance.
It would be more compelling if you could produce some numbers to counter the report e.g. are ground staff paid above the average wage in the local area? It may be short on numbers, but it has the ring of truth to me....