|Can you recheck the adapter model number(s) please. I went to the UK TP-link site and there's nothing (even remotely) resembling the details give above?|
What is actually written on each of the modules?
I haven't used any homeplug wifi extenders (only the cat-5 versions by Devolo); but my understanding is that they do not require a password by default. Although (if similar to cat-5 versions) there is usually an option set one... if you wish to.
Have you plugged your Virgin router into the TP Master module (with a cat-5 cable) as likely that's what is required? presuming one does need that cat-5 connection, then the other modules may then simple radiate (extend) your signal as wifi?