I'm going to buy the monitor separately, looking at something like this for the moment: https://www.currys.co.uk/gbuk/gamin...r-black-10211874-pdt.html?intcmpid=display~RRDo you have another Window's PC or laptop you won't use after this? Even if it's not a custom one you can take the copy of Window's from it which will save £85 which is a lot of money for a build at this price.
Also is the monitor one you already have or will you need one? If you'll need one, is it included in this budget or do you have a seperate one for it?