Its funny doing work for civil servants, they are often the first to challenge the quote/estimate and when im offered cash price its almost always a civil servant./ council worker etc. read in to that what you will. One woman was a investigator at DWP/Job Centre and wanted cash price - told her nope... another was a magistrate/JP wanted to pay cash for the charger install but still claim his OZEV grant! the irony... All like to think holier than thou..
The funniest of them all was a job in Bristol and the guy was a union rep and thought my hourly rate was too high, also wanting to pay cash if i lower it, i told him that its okay for his chums to walk out causing havoc on the trains for higher pay but not okay for me to charge a decent hourly rate. Who was he to judge if my rate was too high, eitehr he wanted the job doing or he didnt... he paid the quoted price in the end and a sizeable deposit upfront as he annoyed me.