some examples of what you can get for your cash http://www.cyberpowersystem.co.uk/system/XplorerX6-9120Notebook/ , http://www.pcspecialist.co.uk/notebooks/optimusIV-17/. I don't know the specs of your PC , but if it is a good one , I think you will be quite disappointed with the performance of laptops in this price range . perhaps a better alternative would be to purchase a PC to keep at mum`s , you will get better value for money . Also if you are up for it , possibly build it yourself as an example you could get something like this for your money http://3xs.scan.co.uk/ConfigureSystem.asp?SystemID=1510 . Hope you find this useful .
What is ransomware and how do I protect my PC from WannaCry?