I'd have thought recoding the programme guide would not be a major job for the world's largest TV manufacturer.
Anyway I got rid of my LG and bought a set from it's biggest competitor. Instantaneous programme guide.
To be fair to LG it has a far better signal diagnostic. The competitor only shows "signal quality" whereas the LG diagnostic shows signal strength as well. It also shows a list of the TV channels on each Mux . Good signal diagnostics are essential for pointing your aerial, especially in weak signal locations.
I also complained to Which, who consistently rates this TV as a best-buy. It has actually mentioned the slow programme guide for some sets, but it doesn't reduce the number of 'stars'. They said they would pass my complaint on to the reviewing team, but no change in recent ratings.