£14k obviously your boss earns too much to forget a cheque of that size just lying around. I'd like to think I'd go out of my way to bank it within 2-3 days if not immediately.
As for cheques not being accepted its a terrible inefficient system. You have plenty of better options like bank transfer, cash, PayPal, etc. Using cheques today is like using morse code. Most places refuse them.
You do now yet you seem to be having a go at people who have loads of cheques from 10, 20 years ago. The world was a much different place with more money exchanging via cheques than bank transfer, cash, paypal etc.
Hell cheques are still used by a lot of businesses today. We are building a new house for a client and monthly staged payment from the mortgage company comes by cheque in the post every month and we are talking about £150k per month.