This is interesting, there was another thread recently about this and it was also said the issue was specific to Gold +1.
To me it makes sense that old programmes are shown in their native aspect ratio (4:3), what I don't understand is why this would differ between a channel and its time-shifted counterpart. Can only guess that Gold are aware that some people prefer to watch the programme in its original aspect ratio whilst others prefer it in 16:9 as they dislike the black borders. By operating in this way they are essentially giving their viewers the best of both worlds.
Personally I dislike a 4:3 programme stretched out to 16:9, makes faces look unnaturally wide.
Regarding the adverts on ITV, completely normal. Some adverts are shot in a different aspect ratio.