One immersed in the part of 'Sir Bedivere'? (5)

I believe the answer is:

diver

I'm a little stuck... Click here to teach me more about this clue!

'one immersed in' is the definition.
I can't judge whether this definition defines the answer.

'part of 'sir bedivere'?' is the wordplay.
'part of' indicates a hidden word.
'DIVER' is hidden in the letters of 'sir bedivere'.

'the' is the link.

Can you help me to learn more?

(Other definitions for diver that I've seen before include "Person operating under water" , "Large waterbird" , "Frogman" , "Grebe maybe" , "Water bird" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app