It really isn't that difficult
As they say, to "err" is human but to really f**k things up requires a computer. I, funny enough, am human and I "err" sometimes. To be fair after 28 years of experience in this field my err'ing is few and far between though.
The install was really straightforward, two Ubiquiti long range WiFi access points both talking back to a cloud controller. One in the main factory, one in the admin block and between them they'd have the site covered. The access point in the admin block was no bother, the poe adapter was installed in the comms cabinet and the access point replaced two existing "home style" units. With the Ubiquiti Unifi setup it's also very easy having one unit broadcast up to four separate wireless signals (the "SSID" stuff you may have seen on your phone / laptop). The SSID for the staff was on one VLAN and the guests on another and with VLAN tagging via the setup on the cloud controller the staff could see the internal network and guests could only get out to the internet. If I'm getting too geeky and you are thinking what on earth is a VLAN head over to a VLAN explanation here.
So, as I said I err'd....
With the access point happily doing its thing in the admin block we went and installed the access point in the factory, fifty feet up in the roof space - luckily they had an access gantry and my cabling guy had all the necessary harnesses and working at height certifications. I had the easy part at ground level at the wiring closet. The poe adapter went in and it was patched into the data switch. The "blue ring" lit up on the access point up above and I could see the SSIDs appear on my phone. All sorted ! Hmmm, no. Within a minute the blue ring was a flashing blue ring and in Ubiquiti Unifi parlance that meant that there was a problem with the configuration somewhere. Didn't make sense, the port that was being used on the switch had the correct VLAN tagged assignment to it and so did the uplink port to the main switch in the admin block. However I had assumed ! Assumption can make life easier but (as I should know) it can also make an easy job into a prolonged one. My assumption was that the uplink port on the switch was actually being used as the uplink. It was not. Port 24 was not the uplink, port 19 was.
Scratching of head over, I gave port 19 the relevant tagged vlan assignment and the steady blue light came back. The moral of my story here is to remember to check the data switch setups before installing my access points because at the end of the day it really isn't that difficult.