New
#21
Here's a newer alternative, although the lowest price models are just over the £100 limit: GTX 1050.
Example: https://www.amazon.co.uk/EVGA-Geforc...words=gtx+1050
I'm not sure, but it may be the best graphics card you can buy that doesn't need an auxiliary PCI-E power connector. It's also a current model, so it may have driver support for a long time.
However, it really wants a 300W PSU or better. You seem to have never checked what's in the DT1404. (Every PSU I have seen has a sticker giving its ratings. The sticker is not always readable with the PSU installed in the case.) I strongly recommend that you give it a look. Otherwise, the advice you're getting is of limited value.