The two letters from Ian (6)
I believe the answer is:
botham
'ian' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'the two letters' is the wordplay.
'the two' becomes 'both' (synonyms).
'letters' becomes 'am' (I can't justify this - if you can you should give a lot more credence to this answer).
'both'+'am'='BOTHAM'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for botham that I've seen before include "34 [CRICKETER]" , "Cricket pundit" , "Ian -, Eng. cricketer" .)