I found this site http://www.saynoto0870.com/search.php and entered Travelpack and it gave some alternatives: 0161 707 2229 and 020 8585 4000. Don't know if they'll work but might be worth a try
Already emailed them but they did not respond in time.
Thanks for the phone number suggestions. Eventually got through and flight had been cancelled. Thanks for helping me, otherwise I would not have known there was no flight!