Bush 43 Inch Smart 4K UHD HDR QLED Freeview TV - £259.99 (Free Collection) @ Argos

Bush and Alba (And Hitachi) are all own brands of Argos. They just sign a manufacuring deal for the lowest bidder to produce TVs for them and slap their brand name on the box.

Same goes with Technika at Tesco, Polaroid at Asda, Techwood at AO and Morrisons etc.

Some models will be made by UMC (The people that manufacture Sharp TVs)

But this particular model in question today is made by Vestel - A Turkish company that also make TVs for Panasonic, Toshiba, JVC and brands like you see in the shops as named above.

I don't believe all stuff from Turkey are low quality. Costco would not be offering 3 month returns and 5y warranties on the new Vestel models (both 'Panasonic' and 'Toshiba' lines such as the UK4D models now available up to 65") if they were of such poor quality. Costco buyers aren't exactly the easiest to convert. The 65UK4D and 5D 'Toshiba' models have excellent picture quality for the price point, having seen them in showrooms next to LG's and Samsung's costing £100's more. Certainly Vestel had a reputation for questionable quality in the past but even the technical press comments on their new lines are very favorable.
My fridge-freezer, washing machine and tumble dryer are all Beko and have worked flawlessly over the past 4 years, having switched from Zanussi, Hoover and Samsung after regular repairs and untold misery within the first few years. Some Beko white goods are now 'Which' best buys.

Well Costco offer the same Vestel TV lines (UK4D and UK5D models) in Toshiba guise with a 5 y warranty, the consensus is that there's a step up in reliability and picture quality with these newer Vestels.
At this price, I'd say it's worth a punt even without a 5y guarantee.

QLED is just the latest branding change for LCD, it's meaningless in terms of performance.