I have a good condition concertina pipe if you are interested. I know this sounds silly but have you tried spinningg the pipe around because I don't think they are equal lengths Lest
I got one from ACT and you have to have a bit fiddle with the AFM, as in lossen the mounting bolts and use a thim round file to make the hole in the GRP a little bigger. This will allow you to to aline the AFM to the hose.