Decent type attached to leftie sort of university (8)
I believe the answer is:
redbrick
'sort of university' is the definition.
'decent type attached to leftie' is the wordplay.
'decent type' becomes 'brick' (brick can mean a dependable person).
'attached to' says to put letters next to each other.
'leftie' becomes 'red' (red can informally mean a political leftwinger).
'brick' put after 'red' is 'REDBRICK'.
(Other definitions for redbrick that I've seen before include "not Oxbridge material" , "Type of university" , "Style of university" , "Non-Oxbridge" , "(Of universities) late 19th- to early 20th-century" .)