Has anyone thought of paying an hourly rate and just giving the employee X amount of £s work to do in the day.
I.e. In 6 hours I expect you to clean this amount of houses for £8 an hour. If you don't, (without good reason - as specified in contract) the difference will be minused from your wage.
I think that's fair.
For a start you cant pay them less than the minimum hourly wage no matter what they achieve, but what you have described
is just another bonus scheme and therefore will have all the problems that come with bonuses.
For example lets say the employee has a target of 20 properties but gets off to a bad start so wont reach the required amount,
not much incentive left other than to faff about for the rest of the day and get the minimum amount anyway, or worse forget
about quality and take shortcuts to pull the amount back hoping the customers wont notice or complain.