Have been scratching my head, and as usual, the answer is (hopefully) starring me in the face
Change line 98 from...
$difference = strtotime("2 January 1971");
$difference = strtotime("now");
you can test by changing the new line with
$difference = strtotime("next Friday");
which should give you a different result.
The original code was comparing the unix timestamp date (the number of seconds since January 1 1970 00:00:00 UTC) with 2nd January 1971, which will always be the same, whereas we want to compare the time difference between the timestamp date and now
Hope it works this time.