Unfortunately your engineer appears to have changed his opinion since his visit to suit Samsung taking this no further!
He observed that the rear volume issues renders the rear speakers useless in wifi/hdmi modes, and stated I should continue using an optical connection and two controls until the issue can be resolved; so I am finding your description of his findings very difficult to understand.
This is not operating at an acceptable level in any way shape or form, and I will not take this lying down; this system was working fine on all connection modes out the box (apart from wifi issues), up until a firmware update caused a plague of continuing issues. This is not simply me being unhappy with a product I purchased but unhappy with Samsung screwing up the firmware post pirchase. I also note there is no mention of the other issues we have with the soundbar, and take it these are just being swept under the carpet.
It appears Korea don't value their British customers in any way and have come 80% of the way to fix the FAULTS, and simply now think they can walk away with the usual large corporate attitude. This has gone on far too long now and we have been entirely patient for months and months; I will now be looking into how some class action could be brought against Samsung and I am sure I will have some volunteers to protest in some way (peacefully) outside your head office.
Very very very disappointed.