My information came from a previous apprentice scheme application, the application was not successful so I applied about 9 or 10 months later when the scheme was open again and I got the message that I had already completed the online tests.
This confused me (doesn't take much to confuse me) so I contacted Jet2 recruitment who told me that the previous test results last for 12 months so the results from my previous application were still valid.
If there are current applicants who are being denied the online assessments who have not applied before or who applied more than 12 months ago then they should contact Jet2 recruitment directly, whenever I have emailed them they have got back to me pretty promptly.