The January 2015 edition of Classic Cars magazine ( UK ) carries an article on the value of the 401 and 403 relative to Astons. There is an interesting graph which purports to show the rise and fall in the 401/3 market from 1987 to present day.
These magazines seem to be given publishing dates which stretch increasingly further into the future from the actual date of publication. For anyone who may be wondering why this happens ( nerd that I am ), I have enquired. Apparently, the reason for this is that casual readers approach the rack of magazines in shops at railway stations and airports for something to read on the journey. They will, more often than not, simply choose the magazine which appears to be the most recent, rather than choose by title preference.