since you can't attend the open days, you kinda have to rely on which you feel more drawn towards which appears to be Sheffield, and that's perfectly fine. unless you care about going to the next best uni for aerospace engineering known to be Bristol, i don't think it matters that much because both uni's are likely to provide a more than decent experience for you, even if Bristol's facilities are outdated. Sheffield does appear to be more convenient for you in more than one aspect (the location, the learning environment, and the course rating), so if you feel that's best for you then go for it. but either one would be good i hope so trust your gut.