would he not call down with all 1 pair hands?
put yourself in his position. he has 3bet to £42 and got 4 callers, a terribad fish whos likely range is 1 pair bets £15 into like 100+ can you really ever see yourself folding. if hes a good player he will think he is good too. if he has 1 pair he obv doesnt want to raise fold, but if the dfish3bets the flop he'd have to fold. basically he's been put in a position where if he has air he basically has to raise especially live where you get so few decent spots as playing less hands etc. I actually think if you have air yourself here that 3betting the flop would be quite cool as he def folds AA and its hard to flop sets
also number one guy will probably fold tptk kinda hands because its a protected pot and the guy who 3bet pre and 2bet (ew) the flop is still to act. basically caught in the middle of two guys who want to put alot of money into the pot repping very strong ranges which crush tptk kinda ranges.