Result...... Downloaded Stellarium Scope and also updated ASCOM platform. Ran SS and left everything as default and followed on screen prompts to delete existing .ini files and then re-ran Stellarium. When back into SS, set it up for Celestron and connected fine. Updated the Stellarium settings and then launched Stellarium. Did a slew and away goes the mount. Now the big test......started AT and said 'Connect to my mount'. Low and behold it did. Back to Stellarium and issue another goto this time way over the other side of the sky and when it starts moving, back to AT to see that it has updated the target and shows 'Slewing' and current mount positions. Am a very happy bunny and also even happier that I did my de-bugging the warmth of my 'Geek Room' as Mrs S calls the 3rd bedroom that has been given over to me in new house. Think I may have also solved my guiding issue, but not yet been able to test it out in anger. Whne i was de-bugging i connected my D7100 via the USB extension cable that I had the QHY connected to yesterday. Is a 10m jobbie, but has active repeater in. When I told AT to solve it took an age for the command to get to the camera, so reckon the cable may be causing a few delays which the QHY does not like. Will be getting a plain USB extension as can put laptop closer to mount and see if that makes a difference. Now just need to get out and all should be good. Cheers