I hope you have better luck with the HDMI upscaler. I could not get an upscaler to display all the QL screen.
I gave up and got a refund. Now using a GBS8220 to a VGA screen, all perfect no missing columns.
I have had mixed results with the scart-hdmi upscaler, which I bought at the time of the original discussion on here.
At the time, I used it with a Technika TV (my kitchen TV at the time!). Using a simple QL 8-pin DIN to SCART lead, I got a good quality picture, but the usual loss of a few characters at the edges of the picture. With the upscaler, it gave a good full 512 pixel display and I had nothing but praise for the device.
More recently, I've tried it with other TVs and monitors which have HDMI inputs. Mixed results - some do as well as the Technika, others fail to "upscale" at all, or give a poor quality picture.
Fiddling with settings on the TV sometimes helps me, one of the TVs has a setting (can't remember what it's called) which prevents or allows upscaling to happen. Not sure how it works, maybe it prevents the TV and upscaler both trying and fighting to adjust the display.
I also remember the late Lee Privett (former Quanta magazine editor) suggesting the use of a device from JS Technologies which went between a SCART connection and a SVGA input on a monitor instead of HDMI. It's fairly expensive at nearly £60, but if you asked them nicely (i.e. mention it's to be used with QL on ordering) they had a version which was slightly attuned to allow full QL display. http://www.js-technology.com/store/category.php?id_category=5. Lee wrote an article on the subject in Quanta mag once, I'll see if I can find it and scan it for people to see,
Things have of course moved on since those early upscalers such as mine and there's more choice and prices have largely come down.
EDIT: Found the article (from Quanta mag June/July 2011, and it's by Dr. John Sim, not Lee, sorry):
See also an article at http://www.dilwyn.me.uk/docs/hardware/ql2vga.pdf