Dave
Weuse pre done carbon copy we have one thats 2 the other 3.
If no one in they get it signed & dated & pushed through letter box, that then is sent with invoice & we keep a copy on file.
Or if in they sign & recieve top copy, we invoice as above.
All company details on carbon, a copy of our letterhead & space for comments etc.
These are made for us by a local printer & are only pence each, but, you have a full papertrail of working day per van & all info is logged in writing & signed.
We also sign so you have a log of employee who carried out work.
Gary