Looking for laptop for running ebay store (15"+, UK, max £600)

As per the title, I'm looking for a laptop in the UK with decent build quality for running my ebay store. Usage 70% on a desktop, 20% on my lap at home, 10% on my lap at other locations. Thanks in advance.

• Total budget and country of purchase: £600 (UK) but without spending unnecessarily.

• Do you prefer a 2 in 1 form factor, good battery life or best specifications for the money? Pick or include any that apply. Good battery life.

• How important is weight and thinness to you? Not at all.

• Which OS do you require? Windows, Mac, Chrome OS, Linux. Windows

• Do you have a preferred screen size? If indifferent, put N/A. 15"+ ideally.

• Are you doing any CAD/video editing/photo editing/gaming? List which programs/games you desire to run. No games. Only real processing will be adding watermarks to images in bulk and some number crunching on spreadsheets.

• If you're gaming, do you have certain games you want to play? At what settings and FPS do you want? N/A

• Any specific requirements such as good keyboard, reliable build quality, touch-screen, finger-print reader, optical drive or good input devices (keyboard/touchpad)? Optical drive required as occasionally need to test CD's and DVD's for errors. Numeric keypad on keyboard and decent keyboard quality as a large part of my work is working with numbers and typing into spreadsheets. I know fully rugged is beyond my budget, but prefer a laptop which is semi-rugged or good build quality as my last laptop isn't that old but is already falling to bits. Long battery life specified because I've used my current laptop mostly with the power cable plugged in and having had the power socket repaired it's on its last legs again so prefer to use unplugged when not at a desk. Quality of touchpad unimportant as I always use a usb mouse.

• Leave any finishing thoughts here that you may feel are necessary and beneficial to the discussion. Reliability is of utmost importance as ebay is my sole source of income. Reliable wi-fi (old laptop sometimes loses wi-fi until I reboot). 2 or 3 USB ports preffered, HDMI output not important. Full HD screen not important as don't watch movies on it. Other than ebay just used for general browsing. Operating speed is important, don't want to get frustrated waiting for a chugging laptop to be ready to use but I'm a bit/lot out of touch with what's necessary as a laptop processor.

Thanks in advance.