Hi Evan, it would appear that no one has the answer to your question. I had a similar query, which you can read here, some of the replies may be useful? (although regretably I think some of the pics may have since been removed from photobucket) -
http://www.hitchcocksmotorcycles.com/fo ... ost_102223
As you can see, I wasn't looking for rear sets as such, just wanted to move the pegs back slightly. I'm assuming that the 80 quid set would require some fabrication to fit? In which case modifying the existing pegs may be a viable option. Otherwise I think you may have to bite the bullet as it were, and shell out the 300.
good luck