Front Locker Gas Struts

ClubMemberFB08446F1A

I recently purchased a s/h Sprite Major and quickly notived the front locker gas strut did not support the locker door, I decided rather than go back to the dealer who are in Nottinghamshire (too far to drive) to just order one online from a manufacturer
in Derby, I fitted the new one easy peasy but had the same issue as with the old one, bearing in mind I had been careful to seek their advice etc regarding pressure rating 100n they are now offering to add more gas to it but advertise this strut specifically
for Caravan Front Lockers?  Its going to cost me a third of its value to send it back ... and begs a question regarding the one that I thought was failed which I replaced with the new one?

Any thoughts/ideas ...?