Sadly wireless networks are difficult for the average person to troubleshoot and are less than reliable for 101 different reasons. There is a tendency to think if you have a rock solid wireless experience (and it certainly can be reliable if the stars are aligned), that it is because you have done it right whilst others have done it wrong. The truth is, you can do everything right but there are just some limitations imposed by circumstance (the building you are in, other sources of RF like microwaves and older digital phones, how densely populated your immediate area is - my mobiles devices have been known to detect 64 wifi networks with moderate to high signal strength at home before) that will just confound your efforts.
The most aggravating pattern being that connectivity fails for one device and seems to work flawlessly for everything else. But I assure you, Naim products are not the only ones to suffer.
We have about 15 wireless devices at home. Anything that can be wired up is, but tablets and phones and stuff accumulate. A couple months ago, my wife's iPad refused to connect. No matter what we did, it claimed that the router rejected the password. As the resident IT person at home, I got the blame. She wanted to sling it out the window. The settings were correct. The other devices, including other iPads worked fine. The log on the router showed no connection attempts at all.
The problem them intermittently fixed itself a month ago and then recently completely stabilised. Now, it could just as easily have been any other device in the home but the problem picked out that one item. Throughout all this it was fine with other networks out of the home. To top it off, I have the tools, training and knowledge to analyse the issue deeper and it is often what I do all day in my day job anyway but with a bunch of kids and operating in an already sleep deprived state, I could not be arsed. The average Joe stands no chance.
I had another device that would lose signal and report that no networks were available for a variable 20-40 minute period every night for some time between 11pm and 1am which I also never got to the bottom of.
For everything that matters go wired. Even with a wired network, there are enough things to muck up without bringing wifi protocols into the mix.