at least 5 CL games, 4 at PL prices all sold out adds a pretty large amount, plus gate receipts last year were £62m I think so feasible it’s nearer £80m this year
But I don't think the figure you quoted are just gate receipts ,quick look at basic accounts published in various outlets has match day revenue at 62 million and as Craig points out the new stand may increase that too £ 80 million . But just season tickets ( £900 tops) and general admission prices are not the only thing thats Inc In match day revenue , to me it looks like all corporate hospitality , beverages , food etc is Inc in them figures .
If there correct and just general admission prices generate say £40 million pound Inc season tkts then a 20 % cut of ticket prices would cost the club £8 million , a considerable sum but one that's being dwarfed every time there's a new tv or corporate sponsor announced .
You mentioned the champions league but aren't them match day revenue figures also for the year up to may 2016 When we would have had match day income from a Europa league run that had us play 7 home games possibly all full houses .