We have over half our money through BACS now, its much better!!
As above just get the custy to use the first line of their addy as ref, then all we do is on a Friday log onto online banking and work down the list ticking off on the work sheets whos paid, simples!!
All we do is leave a SAE, with NO stamp and a slip stapled to the back saying cleaned today, send chq for £xx.xx or pay via bacs to sort code xx-xx-xx acc number. Leaving no stamp sort of pushes towards making them pay via bacs, but as we all know there are still the idiots that owe come next clean!!!