Hey guys, i think i understand why this problems is happening but first ill explain. after completing the halo 4 campaign solo on legendary i got my achievement lone wolf legend proving i have finished the campaign. on my halo 4 service record it says i have completed the campaign on legendary, but i haven’t been given my armor perm? i have now come to realise that due to finishing certain parts of the campaign while offline for some reason it hasn’t registered the completion but if anyone can help me fix this instead of replaying the campaign solo again that would be great! thanks guys! 
Your suspicions are correct, you must complete missions 1-4 on legendary whilst online. There is no ‘fix’, for anything to register on your service record it must be completed online.
At least 1 and 3 are absolute cake, recommend youtubing the skips for 2, 3 and 4 if you just want to get them out of the way - plus they’re quite interesting (skip alpha and tank section of infinity - use catch skull for easy knights, glitch through the shields on reclaimer + out of map skip, not many skips for forerunner but you can run past tons of enemies, also skip final battle on dawn).
Unlucky bro!
ah well thanks dude ill search that now, iv got a free day so ill do it today thanks allot for the reply it really helped!
Good Hunting-