Technically it's not the officers who choose to respond. It's command HQ and the sgt's who decide. If people truly knew how many police offers are on shift at one time believe me, you would be shocked. It's so little it's alarming.
They do have to decide what's more important. This is the kind of case where someone would book to visit you another day most of the time. For example a burglary would take priority or an assault.
For an example my local police force I have called when there was a huge domestic going on below the old flat I used to live it. To the point the guy was telling the lady to stab him, go on do it. I rang 999. 45mins later they turned up. Lucky she didn't stab him.
Also as some know I'm a doorman - not much anymore - myself and a colleague ended up us 2 vs 4 guys. They attempted to glass us and a fight broke out with just us in a packed venue. The paramedics refused to turn up to stitch my partners lip up after being glassed and the staff called the police before the fight even broke out and again approx 45mins after the incident and glass everywhere with us getting them out the door, a PCSO, that's right a PCSO, turned up on his own because they were busy.
I don't hold any hope out for my local services.