The 15 inch version of the laptop I currently own is for sale for £949. Identical specs to mine except mine has a 17inch screen.
Runs Planet Coaster very well on high settings.
https://www.scan.co.uk/products/156...MI9tXkhrj03AIVGOd3Ch1f5wW-EAQYAiABEgJg7PD_BwE
Although if you can get a GTX 1060 with 6GB graphics rather than 3GB it will benefit going forward. Although it is not essential.
You could get a laptop with a GTX 1050 or 1050TI for under a grand and it will play Planet Coaster pretty well. But, you can also get one with a GTX 1060 for under a grand. The GTX 1060 is between 80 - 100% faster in games compared to the 1050TI, that's both the 3GB 1060 and 6GB 1060, much much more performance for relatively little extra cost. No brainer really as the GTX 1060 is quite a large step up from the GTX 1050TI.
The good thing about MSI is they are a very reputable gaming brand and build high quality computers. My laptop for example has an i7 7700HQ with a base clock speed of 2.8GHZ and a boost clock speed of 3.6GHZ, because the cooling in the laptop is very good, it happily sits steady at it's boost clock speed of 3.5/3.6GHZ when playing Planet Coaster. The 10 series Nvidia GPU's are also not 'mobile' chips as was the case a few years ago, they are pretty much the same performance as their desktop counterpart chips,
unless you go for an Nvidia card that is labelled as MAX-Q, then they are slower than a desktop card.
Pretty much all gaming laptops will have upgradable ram. Just make sure the computer is built well enough to handle the power. IE, it has good cooling, else the components will thermal throttle inside as a coping mechanism to help with the heat, which results in reduced performance. This is another reason why I sing MSI, they build gaming laptops that can run at that boost clock speeds with the graphics cards running at full pelt for hours and hours and hours in games. With no loss of performance due to heat, the same can't be said for every other brand out there. Although some are pretty good also.
One last thing, try not to buy from PC World. They really are not good value for money. The sell overpriced computers to people who have no clue. Places like Scan, Box, Origin. (which are all top rated UK retailers of computers) Provide much more competitive prices with the big brands, and have much better after sales service. For free with my laptop from Box, I got a free MSI waterproof laptop backpack, MSI gaming mouse and MSI mouse matt. The waterproof backpack is worth £70 alone! On top of the free goodies, the other top retailers apart from PC world also give much better value for money on the actual laptop hardware itself.