Re: From A&A to Z?
For another survey (with self selection for generally more tech savvy users) try this one. That puts AAISP at the top with IDNet (also my ISP) second and Zen third. Only those three rate above 90%. You get what you pay for ;)
My assumption would be that AAISP and IDNet fail to appear on the Which? survey because of cost. A lot (most?) people subscribe to Which? to find the cheapest deal.
VM's almost constant appearance at the bottom of the chart is a sad indictment of the way they run their network. Suck customers in with headline speeds but do the bear minimum to provide those speeds in practice.