You may want to think about follow-up after surgery. Regular appointments for some time after. Just possibly further treatments ( obviously we hope not needed ). Will one country pick up further treatment after t'other has done surgery? Where are you living most of the time etc.
Communication. Will you understand sufficiently different terms /words in Spanish ?
The Gleason 5 element of the biopsy is secondary . But we don't know figures. For example, the 3 could be 51 % and the 5 = 49%. That would = 3+5 . As would 95% grade 3 + 5% grade 5. I'm guessing the Urologist has looked at this regarding speed of action.
If a lot of the grade 5 involved then psa results may be less helpful.
Suspect NHS would want full scan results etc. before treating.
If it is the potentially quicker recovery the robot offers I wouldn't base final decision solely upon that. You want the best surgeon available to do the most thorough job using whichever method.