Albert, a blooming amateur in detective fiction (7)
I believe the answer is:
campion
'blooming amateur in detective fiction' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'albert a' is the wordplay.
I cannot really see how this works, but
'a' could be 'amp' (A is the symbol for the amp or ampere) and 'amp' is present in the answer.
The remaining letters 'cion' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for campion that I've seen before include "Film director" , "Wild flower (red, white or bladder)" , "Here's one blooming" , "Edmund ---, martyr; Thomas ---, poet/lute composer" , "Wayside flower" .)