Mo the caller asked.
Why is everything amplified from one big stack at the front? This is also a problem at ceilidhs, where you can't chose your spot on the floor as you move up and down the set.
the simplest answer is cost. to set up speakers all over the venue and get the sound to appear to come from the right place the artist/band and not behind or to the side of you the audiance requires a lot of processing in delay control, time to set up, and somewhere safe to put the speakers, poles in the audiance will block the view and hanging them requires a safe structure to attach to (see comments about tents failing down) the extra time alone to set up the dance tent properly like this at bromyard would probably amount to a full day on site after doing all the math before hand.
For bromyard and the current small team doing the set up I guess we would have to start on the saturday before, oh sorry we cant the tents are not up yet. ;-)
then it would need H&S to sign off before the audiance is allowed in.