If it was me and i wasnt cleaning, id be there at 7am, get kettle on then fill vans, sort sheets and anything else that needs doing for the lads then as they arrive id be on the case about todays work, a sort of morning brief if you like.
Lay down your expectations for the day, anyone not pulling their weight should be warned and if need be got rid of after a warning.
We have employed at various point over the years with varying types of lads the people who dont put it in we always made sure we told them this, we know the work we know exactly how long each job takes so there is no messing.
They lads we've had that understood what we were trying to achieve we looked after more so than the people who just turned up and did an ok job.
Do you have any on the lads as a supervisor? Maybe getting one of the guys to do this and pay him a little more they can then crack the whip when youre not around, if the £1 per hour payrise or £40 per week, get an extra few jobs done per day it in effect the pay rise is free sort of as they arent doing the work anyway!
FYI the last guy we employed was turning over £200 per day trad, we would stack his day and then say ring us when youre done and we'd send him off or get him doing some of our jobs if he had time.