Yeah I guess it's too new-fangled to have it's own page on TMA. As you say, I reckon the builders incorporated whichever older places looked useful though. so there are links to the Wansdyke page on tma here and there.
I like Maes Knoll
http://www.themodernantiquarian.com/site/2882/maes_knoll.html
and its weird 'tump' which they say is part of Wansdyke (but seems a very useful thing for a hillfort to have).

Thank you PeteG for the link to Wansdyke Project 21, what a wonderful web-site with pages on Maps, Articles, Photos, plus Video Fragments (taken by you in a ultralight aircaraft). When we were on the Ridgeway section of our walk on Sunday a small plane, which I took to be a stunt plane, flew over and went into a loop-the-loop routine (for us I fancied). If that was you, or you know who it was, then thank you, it was thrilling to watch.

On a disconcerting note, as we drew close to Wansdyke we were passed by a 4x4 rally going the other way towards the Ridgeway. The trackways they had driven over were totally unwalkable in places. I have to ask WHY?

Thank you Rhiannon for your friendly and informative (as always) response. I have been into the Maes Knoll link you posted which I really enjoyed reading - must get myself down that way.

Best wishes
t june jackson