Generally, the limiting factors on a business laptop are going to be:
- Processor
- RAM
- Hard disk
For the processor, look for an HQ processor. Don't go for an "U" series or a "Core m" processor as they're low power and very low power respectively (as in the amount of power they use) but underpowered (performance) as a consequence. Some companies sell specialist gaming laptops with desktop processors in, but those will run VERY hot and noisy and you won't find them in Currys!
Something like the i7-6700HQ or i7-7700HQ is pretty close to top of the line (one is a generation older than the other, but they're both very meaty chips).
For the RAM, make sure that whatever you buy can easily be upgraded to 16GB. You're going to see rapidly diminishing returns beyond 16GB so it's not worth worrying about going higher, but 8GB is a bit low for heavy use.
For the hard disk, look for a laptop that has an SSD, or an SSD and a hard disk (the latter can give you the best of both worlds - you stick Windows and your other software on the SSD so that everything loads quickly, and store your actual data on the much larger hard drive)
Oh, and you'll almost certainly want Full HD (1920x1080) resolution if the screen's a decent size (15" or larger). It can be wasted on a small screen because everything's so small anyway. It's utterly pointless to pay extra for 4K resolution on such a tiny viewing area.