not sure if [client] or [gameplay] ; loading screen/post game issue

LOAD SCREEN ISSUE so sometimes it takes a LONG time for my loading screen to come up after champion select sometimes it comes up within 5 second which i'd say is normal and to be expected but sometimes it takes in excess of 20 seconds after the champion select disappears for the loading screen to pop up i have no issues once i'm at the loading screen, and i can usually get to 100% before the last person finishes loading my ping on average is 85-95 so no issues there either

not sure if this is also related to the cause of this but... POST-GAME LOBBY ISSUE as with the load screen issue sometimes it takes excessive amounts of time after a game for my post-game lobby to show up one instance where i was complaining to my friend about it on skype took around 3 minutes for the lobby to appear (timestamps on skype confirm the time frame for me)

only very rarely do i experience lag in-game and it seems to only be just before and just after games that i'm having these issues if anyone can maybe point me in a direction to resolving this that would be great