Coff'
Back in the day (67-73' ) each airframe did about 700hrs per annum, so if 204 was scrapped in '98 and entered service in '67 it did about 20,000hours.
If it had all been route flying at 320knots TAS ( Did the RAF continue to fly at 1010 TIT ? ) then that is 6,400,000 nautical miles. But of course a lot of the flying was circuit bashing and tac' low level, the latter in my day at 190kts - so perhaps reduce the above figure by a third, a figure I have snatched out of the air, so still over 4 million miles!
Perhaps someone should check my figures - the old grey cells aren't as sharp as they were 40+ years ago!