Decided to have a look into this as have a mate near Cheltenham and though it might be interesting to check out having read through as much as I could on their site this event seems weird to say the least. The price of standard play entry seems a bit of a red flag due to just how low it is £100 for 5 days of airsoft, 4 nights of camping and other entertainment, that's £20 a day, you'd be lucky to find a site that would run a standard 6-8hr game for that price let alone a big event.
Reading through the tournament rules though is where this get wild to me though, as while it is possible that a team could win the £100,000 the odds are on the impossible side, this isn't a simple knockout style tournament winner takes the cash. To quickly (as possible) summarize how the 'tournament' works (as best I understand it) there are 10 'heats' over 2 days, these heats are more like challenges though test your aim, team building, etc. where teams can score a maximum of 10 points per 'heat' (100 points total), at the end of the second day the top 4 scoring teams will enter into a knockout style playoff. Now the team that wins the playoffs doesn't instantly win the money they only have a chance to win it, the winning team then needs to play against the 5th - 15th place teams (so a team of 8 against a possible team of 80) if the team of 8 complete all the objectives in the final game they win the £100,000, if the opposing team of 80 wins the money is split among them. However the team of 80 can only get a cut of that money up to £1250 and they must survive to get anything so if only 20 people from that team of 80 survives only 20 x £1250 = £25,000 is handed out. HOWEVER if the team of 8 completes some of the objectives then the £1250 each player receives is decreased for each objective they complete e.g. if there are 5 objectives and 3 are completed and 20 players from the team of 80 survive and each objective knock off £250 then the winnings handed out will be (20 x (1250 - (3 x 250))) = £10,000. Feel free to double check this with the website https://www.operation-scorpio.net/programme as it took me quite a while to wrap my head around it so may well have missed something but that was as best I could understand it.
So the only way £100,000 is getting handed out is if one team of 8 takes on and defeats 80 players or 80 players successfully hold x number of objectives without a single player going down.