“Can you just?” usually means that the would be customer thinks that the job will only take ten minutes, whereas you can see that four hours is going to be tight schedule.
The “slack screw” often means a stripped thread (Most probably an odd ball one!)which means a complete remake, probably with a need to bush the parent material.
Even worse, if someone has already had a bodge at it already, which will entail time repairing that, before actually starting the repair proper.
You’ve seen it, a Metric setscrew forced into a Whitworth tapping. “But it’s got a thread on it”
Tell them that the current laboiur rate at a manufacturer car dealership is something over £160 per hour! (It is!) Have they seen the price of a couple of nuts and bnolts at Halfords?
So at £25 per hour, you would be doing the job on the very cheap.
Howard