@Geofftjones
Hi, please confirm if your powerline device model is TL-PA4010 KIT, if so, it doesn't support WiFi feature thus no need to use WPS button at all, just pair the two powerline devices via pair button on them and then them correctly, they will work.
even for other powerline extender with wireless feature, WPS button is not a must, as the WPS button is only used to clone router wireless settings, without the WPS button, you could still customize the wireless settings for powerline extender manually:
How to customize wireless settings on tpPLC Utility