Just a few points:
1. For your fairly basic needs a refurbished laptop (from a 100% reliable source, that I'm happy to recommend) might well meet your needs. Take a look at these:
https://accomputerwarehouse.com/product-category/cheap-refurbished-laptops-uk
(When buying a refurbished laptop though, from any source, it's always worth budgeting for an extra twenty quid or so for a new battery from eBay or similar).
2. You don't need Microsoft Office. Most ABers (including myself) seem to use OpenOffice:
https://www.openoffice.org/
(LibreOffice, as per Jim's link, is also very good,as is WPS Office:
https://www.wps.com )
3. You don't need McAfee or any other full security suites. The most popular free anti-virus program among ABers appears to be Avast, which is what I use myself:
https://www.avast.com/en-gb/index#pc
4. Windows 10 doesn't come with a video-player but VLC is far better than Windows Media Player anyway:
https://www.videolan.org/vlc/index.en-GB.html
5. Windows 10 machines rarely come with a PDF viewer provided. Adobe's own viewer is free but (despite the fact that Adobe invented the PDF format) it's nowhere as good as Foxit Reader (which is the most popular alternative)
https://www.foxitsoftware.com/pdf-reader/
or Sumatra PDF (which is what I use):
https://www.sumatrapdfreader.org/free-pdf-reader.html
6. Most people probably access their email via webmail these days. However if you want a dedicated email client (akin to, say, Outlook Express) the Windows 10 Mail app is extremely basic. Thunderbird is a far better alternative:
https://www.thunderbird.net/en-GB/
7. If you need other free software, just ask here. For example everyone should have Irfanview on their machines. It's a far, far better image-viewer than what comes with Windows and has some nifty photo-editing tools built into it as well:
https://www.irfanview.com/
(If you'd prefer to have an image-editor that's as full-featured as Photoshop, give GIMP a try:
https://www.gimp.org )
8. Your existing laptop won't suddenly stop working (or get infected with loads of viruses and malware) when support for Windows 7 ends, so you've no need to rush into replacing it. I'm using three Windows 7 machines and, although I've been looking at Windows 10 alternatives (from AC Computer Warehouse, as above), I'm in no great hurry to switch to Windows 10.