I wrote again to the designer of the dysfunctional program files, and to my surprise I not only got a helpful answer, there was an attachment holding a load of extra files. It took a while for the info to filter through my "system", seems that the key to successful printing is the way the printer is set up. The new files enabled me to alter the printer's profile so that it could cope with the new program. At the moment all seems to be going well and the printer is some six hours into a ten plus hour print. I'm not sure what the additional programs actually do, but the original files printed out very fragile poorly finished single wall items, now all the external surfaces are double wall, still a bit lacking in surface finish, but a lot stronger. The part being printed is the third part of the fuselage for a 5omm EDF Hawk T1, the first two parts have been printed, and the trial fit before gluing up looks pretty good so far. I'll not order any hardware for the Hawk until I've finished building it. The model won't cost a lot to fit out, four 9G servos, 50mm EDF, ESC and a couple of small 4S LiPos.