Tough question. Here are some of the front-runners imo
1 Graham Norton - probably the best one-on-one interviewer in the Entertainment cosmos. Could have two or three of the EU Leaders on the sofa, they could share anecdotes about the day they met David Beckham and then stick them in his big red chair, they could state their red lines and the moment they mention no compromise on immigration, he dumps them.
2 Diane Abbott - I would willingly concede any point - financial, legislative, or about the correct curvature of a banana - to bring an end to my interaction with the hard-working MP for Hackney. We could end up owning Calais again, or even our own fishing stocks.
3 Justin Fletcher - The Kiddies' favourite and best Cliff Richard impersonator of our time. The famous British sense of humour, and sign language provided for the more elderly members of the EU Commission. Win-Win. The bookies' favourite, and rightly so.
4 Chris Eubank - the monocled Brexiteer. Some have expressed doubts about his ability to seal the deal, but few have a better grasp of impenetrable jargon and will be handy if Jean-Claude Juncker goes lemon at the pow-wow.
5 Sue Barker - bit of momentum developing behind the former French Open Champion, and it's easy to see why. Corrals fools for a living. Picture board, what happened next, mystery EU official round, and home or away. Perhaps the fairest way to decide. Dark horse.