I am glad it worked, and thanks for the detailed instructions and photos for others.  This sort of information is invaluable as the equipment gets older.

So are you sure that the TV is a MX5000 rather than an MX5500?

I'm not entirely sure. On this website the 5000 is listed as released from 1988 and onwards, my TV is marked with a 1989 production year. 5500 is from 1990 and upwards, but of course there could be differences with regions etc. Maybe it is a 5500, as the inside seemed to be the same when you checked the schematics.

Maybe I should change the title to reflect this?

That "1989" on the back of your telly is not the production year, it's the copyright year of the design.

Anyway, well done! That horizontal shift with RGB input is inherent with all B&O tellies with this similar chassis, so there was nothing actually wrong. The usual setting works when picture is decoded from composite PAL, which introduces a delay. When the set switches to RGB, there is no decoding needed and the picture signals reach the tube earlier with relation to the sync pulses, shifting the image to the left.

I see! Thanks again for the input here on the forum, it's been very valuable as there isn't much other info to get elsewhere on the net. I hope the pictures will help others seeking the same problem!