I would stay with the prangster for a while. Are you comfortable with full rates? Fly it and fly it, .If you want something a little less ugly , can I sugtgest the Kite,
ATs use them to train people and it's something you could stay with to get your B.
Hva e you got your A. If not then that is your first priority.
The A certificate is a bit like a driving licence. It's not saying that you can fly , it is saying that you are safe to learn the next bit without an instructor.
The Kite is now Kitted by flair it is indeed very strong a quite a bit bigger than the prangster, The 40 you have will fly it fine. Or why not go for a 46, that would be really good.
I can honestly say that they fly like a dram no vices at all a really good solid honest trainer, that will last a good deal of time.
If you want to go to a low wing after why not try the "Priory models Sillouete," sold at all the shows, less than £60 a very good kit with jig built fus and foam wings.
a very gentle plane that can be flown as hard as you want.
hope this helps