Edit: I didn't see your edit before I started writing, but that's the same laptop as the one in my second link, just £50 more expensive. Currys might match the price though.
@Liv_October Given what you want, it's actually not that hard at all to narrow things down, at least if you really need a smaller laptop. Among gaming laptops in your price range, the only one that's smaller than 15" is the Asus ROG Zephyrus, and it's also about 1.6 kg, as opposed to virtually all other gaming laptops (1.9 kg and above). There is a 15" Zephyrus model, but it's pretty much a regular gaming laptop with a pretty design.
I checked a few sites for the Zephyrus, and these are the best prices (£980 and £1.050) I saw for the models with an Nvidia 1650 and 1650 ti, respectively; the ti variant is a few percentage points faster in gaming than the regular card. The 1650 can handle Sim 4 on ultra graphics settings now with some room to spare, although that may not be true by the time the game is out of development, but a mix of high and ultra should always be fine. Models with a 1660 ti are more like £1,300 and up.
https://www.amazon.co.uk/Zephyrus-G401IA-Gaming-GeForce-Windows/dp/B08696C4GK
https://www.box.co.uk/GA401II-HE025T-ASUS-ROG-Zephyrus-G14-GA401II-HE025T_2962797.html
Both laptops are in stock on a few different sites, so if you have a preference for buying from a certain store or stores, let me know.
This laptop is also well-reviewed, with good temperatures and game performance, plus a battery life that got a lot longer after Asus pushed an update to fix... something, I'm not sure what. If this isn't what you had in mind though, I can look for other options. However, you'd probably either need to go with a 15" laptop or compromise to some extent on performance, for example getting a graphics card that could handle high settings but not ultra.