Aston used to be bigger than Birmingham but Birmingham gradually absorbed it and it became an inner city surburb of Birmingham (as in Aston Villa football team, Aston university, Aston expressway leading to Spaghetti Junction). It is a deprived inner city area.
Birmingham borders onto the Black country, the industrialised south of Staffordshire, so you might find civil events in Birmingham, Aston, Walsall and West Bromwich from the same family because basically these registration districts are all bordering each other.
Regards
Valda