@zedrally - thanks for that it confirmed I was on the right track.
OK after much messing around it "appears," that
starting from scratch, that neither the white or RGB plugin will enroll any of the LED bulbs. I had to make use of the Android app "WiFi controller 2.0" to get things working:
https://play.google.com/store/apps/details?id=com.cdy.client.remoteLedI enrolled just one bulb using the phone app and from then on I could use the Vera Plugins to enroll either white or RGB bulbs. Beside the ip address and port number, the phone app wanted a username? I can only assume that first time round the phone app is setting up something additional in the WiFi bridge, that we don't know about.
Assuming I haven't messed up, it would be nice to know what this is, so that the plugins could be modified to be totally independent of the phone app. So anyone who is a first time user please try to enroll a bulb, using the Vera Plugins,
before accessing the bridge with any phone app and see what happens.
It would also be productive, if the WiFi bridge "Sys" LED could be used to indicate when a UDP datagram has just been received. The flash rate on the bridge power LED is somewhat annoying as well.
All great stuff and the plugins work well.
EDIT: not sure I have this correct. It may be the case that I'm just too slow with the Enroll button or the two seconds you have is actually shorter? I'm finding the enrollment process to be inconsistent.