I favour Toshiba as my repair shop says they are easy to get spares etc. Also John Lewis as a supplier as they give a 2 year warranty. Have a look at Toshiba and John Lewis websites - a 3i or 5i processor with 4 Gig Ram or more is good. Dell has had some criticisms on after sales service here, and HP have stopped making laptops, and although they will "stand behind" laptops sold now, I would, personally not favour that brand.
OnePlus 5T review: Hands-on