My worst mistake when starting out was using my personal savings to setup and not having a separate bank account. A business should pay its own costs, they shouldn't come out of the owners pocket as they did mine for the first 12 months I was cleaning.
If I could do it all again, a business startup loan would be top of the list, separate accounts from day 1, and me just taking a wage after all the expenses, tax and vat is paid.
I'd also go for a bigger van first day (Relay/Ducato/Boxer size), and go straight for the van mount + backpack setup,... forget the trolley, it just doesn't suit my work.