Thanks to everyone for your advice. I have now managed to get this working. My problem was down to a faulty cable going into the effects loop of the amp. Incidentally, my Orange tube amp sounds much better using real pedals rather than those from the Helix. The distortion pedals, especially my Suhr Riot, played through the clean channel sound more dynamic, whereas the distortion pedals in the Helix sound a little harsh. I guess someone could manage to add an Eq block and tweak it to get near to the sound produced using the real pedals, given time. Having said that, the helix modulation, delay and reverbs do sound good through the effects loop. My conclusion is, stick with the real pedals for now and try again when I have more time to tweak until my heart is content. Taking one unit (The Helix) with its multitude of effects, has got to be more convenient than a case of half a dozen heavy pedals and potentially dodgy connections.