Reduce maximum invoice payment times from 30 to 14 or even 10 days, at least for payments under a certain amount (e.g. £1,000). If you don't have the money to pay me, don't hire me.
Compulsory use of either escrow or an up front deposit for jobs over £50 in value.
Government backed holiday pay, even if we have to pay a couple of percent extra tax (with 100% of it being returned once or twice a year as holiday pay).
School children to be taught how to be self employed.
The moon on a stick.