I'd recommend you go shopping for a refurbished laptop (still 1 years Dell guarantee) on the Dell Outlet website. There's no 17" models currently within your budget and just one 16" model - keep checking back though as the stock changes very frequently.
https://www.dell.com/en-uk/dfh/shop/...shed/cp/outlet
If you have any students in your close family, get them to get you another 12% off!