When you say about 15", does that include up to 15.6", which the most common size, and where the value for money is because of that, or something smaller? The reason I ask is firstly for clarification, and secondly, from my experience, I have had two 15.6" and eventually found them a bit heavy, especially when travelling abroad. But as I said you get better value with 15.6" laptops because they are more common, have more space to play with, and have more component options, especially for screens, but at the cost of size and weight.
So for my current laptop I went for a 14" laptop which I customised from a Novatech base model. They don't seem to be doing something similar to what I got atm. So I went over to PCSpecialist, where I got my first laptop many years ago and configured one there. Compared to mine, this has a faster processor, (i7 v i5) slightly larger SSD, (512Gb v 256Gb) twice as much RAM, (16Gb v 8Gb) and faster 2nd 1Tb HD (7200rpm v 5400rpm) than the one I got about 2 years ago from Novatech. It is a very similar case, though this one has a USB3.1 connection which mine does not have. At the time mine was £560, (though I got one with no Operating System) all the spec below is £820, which for the improvements over the one I have seems good value.
Saying that you could get specs similar to mine and save money, as my laptop has no problems with Lr on the rare occasions I use it, or Photoshop which I use more often, but if you want to futureproof yourself below should keep you going for awhile. My 2 year old spec is still fast enough for me. Be aware that the smaller size laptops generally don't have space for an internal CD/DVD if that is important.
Chassis & Display
UltraNote Series: 14" Matte Full HD IPS 60 Hz 45% NTSC LED Widescreen (1920x1080)
Processor (CPU)
Intel® Core™ i7 Quad Core Processor i7-8550U (1.80GHz, 4.0GHz Turbo)
Memory (RAM)
16GB Corsair 2133MHz SODIMM DDR4 (2 x 8GB)
Graphics Card
INTEL® HD GRAPHICS (CPU Dependant) - 1.7GB Max DDR4 Video RAM - DirectX® 12
1st Hard Disk
1TB SEAGATE 7mm SERIAL ATA III 2.5" HARD DRIVE WITH 128MB CACHE (7,200rpm)
1st M.2 SSD Drive
512GB ADATA SU800 M.2 2280 (560 MB/R, 520 MB/W)
Memory Card Reader
Integrated 6 in 1 Card Reader (SD /Mini SD/ SDHC / SDXC / MMC / RSMMC)
AC Adaptor
1 x 40W AC Adaptor
Battery
UltraNote IV Series 44WH Lithium Ion Battery
Power Cable
1 x 1 Metre Cloverleaf UK Power Cable
Sound Card
Realtek 2 Channel High Definition Audio + MIC/Headphone Jack
Bluetooth & Wireless
GIGABIT LAN & WIRELESS INTEL® AC-9260 M.2 (1.73Gbps, 802.11AC) +BT 5.0
USB Options
1 x USB 3.1 PORT (Type C) + 1 x USB 3.0 PORT + 1 x USB 2.0 PORT
Keyboard Language
14" ULTRANOTE III SERIES UK KEYBOARD
Operating System
Genuine Windows 10 Home 64 Bit - inc. Single Licence [KK3-00002]
Operating System Language
United Kingdom - English Language
Windows Recovery Media
Windows 10 Multi-Language Recovery Image - Unlimited Downloads from Online Account
Office Software
FREE 30 Day Trial of Microsoft® Office® 365 (Operating System Required)
Anti-Virus
NO ANTI-VIRUS SOFTWARE
Browser
Firefox™
Notebook Mouse
INTEGRATED 2 BUTTON TOUCHPAD MOUSE
Webcam
INTEGRATED 1MP HD WEBCAM
Warranty
3 Year Standard Warranty (1 Month Collect & Return, 1 Year Parts, 3 Year Labour)
Delivery
STANDARD INSURED DELIVERY TO UK MAINLAND (MON-FRI)
Build Time
Standard Build - Approximately 4 to 6 working days