From time to time placing mega parlays with very very high odds,
for example combining 3-5 ways on correct scores, or doing 8-14 ways parlays.

Only the bigger Sports books have limits of 500k, 1000k or 2000k gbp.
Has anyone an advise or experience which bookies would have tendencies to make problems if hitting such parlays and which one will likely simply go straight forward paying...

Also Marathonbet.co.uk, Coral have most often best odds for this, I for example stay away from placing insane parlays on Marathonbet. I think Bet365, Williamhill etc. are generally trust worthy and would pay in such cases, but their odds aren't exactly the best.

Does anyone know about examples where bookies have paid out big parlays and about examples where bookies tried to fool/scam deny to pay out on a big parlay?

Do you think Betfair Sportsbook will be a good place to do mega parlays, and what about Betvictor?

What Sportsbook would you recommend for big parlays and which ones would you clearly stay away from?

(I use Pinny,Matchbook and the Asian bookies for my regular single bets, but this question is about mega parlays about huge 6-7 digit potential wins, I am ind of playing them instead of Lottery)