[CRASH/DISCONNECTION] After latest patch (7.2) i can't remain in game more than 5 minutes until

My friend and I recently played a few games on Oceania (We're from Melbourne) and we both randomly disconnect after barely five minutes in game. Due to other friends (From New Zealand) we were able to devise that we weren't actually disconnected from the server. There was no message in game stating that we had D/c'd and our champions remained in place until death. We were both still able to use the chat function to personally message people while staring at a frozen disconnected screen. All attempts to reconnect just followed with an unable to connect to server issues yet we could use the chat perfectly and even receive the scoreboard at the end of the match the instant it finishes! There was absolutely no issue with our internet, nobody else on it, multiple connectivity/speed tests all come up perfect. Aside from that we have been experiencing ridiculous server-side lag since about mid December almost to the point where the game becomes unplayable and certainly un-enjoyable. I understand this could be caused primarily by the school/work holiday periods but surely something could be done to improve or stabilize the servers to handle that amount of traffic?? We love this game but its so frustrating the volume/frequency of these problems for a game of nearly a decade old.