It is basic bad manners not to reply to mail.
We always wrote thank you notes for presents etc and ALWAYS replied to mail. I don't mean Spam mail but if someone writes to you it is good manners to reply, even if it is automated at first. I wrote a letter to Sir Richard Branson’s press office, No REPLY! I also wrote to Sir Patrick Moore as I helped him out when he needed something I expected a reply but as usual NO REPLY. This basic bad manners causes the class distinction in England. The upper classes have manners and don't want bad mannered oaf in there midst. So when you are not invited to the upper class things but have loads of money check your manners as a Sir before your name does not mean you know how to behave in good society.
Gordon
