Scott Harrison No one fights better in bar room brawls than a Scotsman with a drinking problem. He is also small, so you have the element of surprise on your side.
If it was my local I'd call David "Harvey" Price.. He could fix the leak in the toilets at the same time
You would want to be on good terms with a Fury they come mob handed. Big John, Peter, Hughie and Young and a selection of other family members and associates. Fat Mick Launching bar stools over the top.
O'Hara Davies; tell him to wait outside, then proceed to tell everyone O'Hara is outside. That should shift the violence to him, 100% effective
Kalle Sauerland, his presence would halt any conflict and his personality would draw everyone together.
plus he would know every back door in every club. And know every bouncer through partying or time spent in the ring !
If this is real life and a practical shout... it would have to Whyte, maybe not the best boxer by any stretch but he is MMA trained and would be far more capable of handing it out in real fight not a boxing match.
I hadn't heard that he was out - but I'm happy to be corrected. According to this article in the Scottish Daily Record he was still in at Xmas and wasn't due out until July '18: https://www.dailyrecord.co.uk/news/scottish-news/caged-boxer-scott-harrison-designs-11748812