In league tables (those dreaded words), Brighton Uni actually fares better than Sussex, despite Sussex being a far better university overall ( I go to both, as I'm doing a joint MSc at both).
The main Swansea University (not the Met - although the Met is exclusively excellent for automotive and motorsport Eng), is very good for engineering. They were the main university working with the Bloodhound SSC project. Cardiff is I believe ranked higher than Swansea, and is of course a Russel group university.