Sonoff SNZB-01 pairing

So I have read most of the threads regarding these Sonoff zigbee devices and I have a SNZB-01 which I am trying to pair. I have follow the instructions previously listed in various threads but what I am having issues with is the actual pairing. I have setup my DTH, placed my app into ‘Scan Nearby’, taken the back off of the button, used a pin to press the RST until the LED flashes x3 times but eventually the scan times out … I have also tried repeatedly pressing the RST pin until the LEDs flash during the scan but still no joy … well no joy most of the times … I have (at the beginning) managed to enrol it as a ‘Thing’ (forgotten how now) then change the DTH and rename it then re-enrol it but I have been trying to recreate this for testing purposes (before I buy some more) and I cannot; after many, many attempts, recreate and pair this device.
Does anyone know a tried and tested approach to always get this device to pair/enrol, rather than ‘scan nearby’ and press the RST button until the LEDs flash?

[UPDATE] I have a few zigbee devices in the house including an Ikea Tradfri outlet in the same room I am attempting to pair my device … so not knowing too much about zigbee and how it creates a mesh I thought having a zigbee device so close it would pair easily but I eventually went out to the garage where my ST hub is an placed the device on top of the hub and attempted to pair that way … and eventually it paired and then after resetting the DTH it re-paired again and although it does work now it is very laggy, I think because it is connected to the Hub rather than the nearest zigbee device. If this is the reason unsure how to improve my zigbee signal and to make it more reliable.

[UPDATE] I had better luck pairing using the eWeLink (ZigBee Switch) option rather than the plain ‘Near By’ option … this has now connected my SNZB-01 via another nearby ZigBee device acting as a repeater and so now my device is much more responsive

I was able to pair my new SNBZ-01, and I see it in the SmartThings APP as “connected.” But, SmartThings does now see it working. I used the Device Handler Sonoff-Zigbee-Button.groovy by Darren Blanchard and Pablo Poo. I’m novice/new at this so patience is appreciated. Is there a way see if a button press is even creating any output from the device? What is a good approach to troubleshooting? -Thanks, Court

If you go into the app and then into Automations then set up an automation for the button to send a message when the button is pressed then this should be a good way to test.