What about the EVGA one then, am I literally paying £30 extra for the brand whereas the card is identical?
And also the case you suggested said the CPU cooler is limited to 58mm, yet the cooler's dimension was 97mm x 97mm x 47mm. Would it fit in this case?
Yes, you are literally just paying for the brand. Possibly a slightly better warranty, but in terms of performance and cooling they will be identical.
58mm referes to the height of the CPU cooler. The dimensions you list are width, depth and height, i.e. 47mm being the height. With 47 being significantly less than 58 you should have no issue.
If you really want to fit this in a suitcase (presumably with other things) as well as carrying keyboard / monitors I really don't see why you would want a cube case. Something like the raven is going to be so much smaller and easier to pack the two won't really be comparable. You also mention having both an SSD and a HDD but again this is something my suggested spec in the raven already had. In fact, the NVME SSD I suggested is considerably quicker than any traditional SSD as it fits in the motherboards m.2 slot (hidden on the back of the board). Effectively meaning you can have a much faster SSD equivalent, a 2.5" hdd for data, and keep a drive bay empty to put another 2.5" hdd or ssd in at a later date for expansion.
In regards to your question about coolers inside something like the silverstone case I really don't think you can get much better than the one I suggested. In all honesty I think your spec is becoming somewhat of a fantasy. Your asking for huge power, with super high end cooling, in something small enough to go in a suitcase. Realistically this just doesn't all go together. If you want the ultra portability you have to accept that things are going to run just a little bit hotter and things will be a little more cramped. That cryorig cooler will be more than capable of keeping something like a 4670k cool at stock clocks and will even support a modest overclock. By the time you are at a GTX 1080, overclocked core i5, nvme ssd, and large storage drive all in a tiny case that can fit in a suitcase this is really as good as it gets. If you want more than this you need to drop your suit case requirement and just buy a normal tower.