I've done that and so far it's working. It's late now but I'll give it a good run tomorrow and fingers crossed...
When following those instructions for the zero config, on my computer that did not come up. After a little searching, I found it's actually under WLAN AutoConfig. I stopped the service, but all that did was cut my computer off completely from the router. I switced it on again and tried just the second part where I double clicked on WLAN AutoConfig and selected disabled from the drop down box at Start Up Type. This seems to have done the trick, although again I'll give it a good test tomorrow with Spotify over Airfoil as well.
Im not that computer literate so was hoping someone could actually explain what it is I've done? I like knowing why doing what Im doing fixes things to increase my knowledge.
Just in case anybody else is in the same boat, I read a lot about changing the channel in airport Utility. I have seen screenshots where this was a drop down box. On mine there was no such option. I think that is because the router is on Channel 6 and if I changed Airport Expressto a different channel the router wouldn't see it. Not sure how to change the channel on my router as this doesnt seem to an option, or at least I can't find it.
Also have read about a robustness option? Where might this be as I cant find it.