The labour cost are either a one off fee. Or if you have staff work out how long it will take in the amount of hours.
so for example if it takes 6 hours to clear the rubbish x 1 person thats £7.00 per hour = £42.00 then add disposal cost and profit.
Dont forhet other costs like Feul, time to unload at disposal site, Charge for site for taking rubbish. Plus any other factors.
Hope this helps