Those specs will easily run current games on the highest settings, but the r9 270x may struggle over the next couple of years, so it might be worth going for something slightly more expensive now and sli two of them later. The processor is ok but an i5 3750k would be better, and if you can afford, it an i7. 8gb ram is fine, as most games are requiring 4 at the moment. If you are looking to upgrade the gpu the nvidia gtx 760 is only around £30 more and is slightly better. if you can afford it you might even want to go for the 770 or 780.
Surface Pro 5 News - release date, UK price, features, specs