[Client] Missing show advanced details button at end game lobby

I got a new computer and ever since I downloaded LoL the "show advanced details button" has been missing from my end of game lobby screen. This is the button that opens a webpage to the match details normally. Everything else about my client seems to be working 100%, it's just this button missing (and I'd really like to have it as I use it each game normally). I have tried repairing my client and emailed Riot Support which directed me to this board discussion. Thanks all.