I don't know if I need receipts. I did ask the insurance company and they told me to photograph everything in the van. Which I did, I even took a video on the phone of me taking everything out, laying it out and saying what it was.
The tool cover in the van is about £70 a year. So if you don't leave your tools on site over night, it would be all you would need. The other premium for the tools on site, is with my public liability insurers. Again that's around £70 or 80 quid a year. I have it, as I will sometimes have to leave expensive tools on site. Powerflush machines, pipe freezers, and tile cutters. Our tile cutter is nearly two grand.
The last one was nicked, but then we did accidently leave it out in the garden over night.