Why do you want to buy a TV from a company that knows nothing about TVs?
The big supermarkets all got their fingers burned dabbling in AV electronics. So much so that both Tesco and ASDA announced that they were pulling back from electronics retail in general. The problem has been that in the rush to offer something cheap they forgot that cheap often means shoddy, and in electronics, shoddy means that the product comes back to bite them in the butt when it breaks.
If for some reason you can only buy from ASDA, then at least buy the best LG you can afford. LG isn't a great make TBH. They're doing the same cost cutting so LG TVs tend to have a slightly below par reputation for reliability. In the end the saying is true.... You get what you pay for.