You can get this if you really try to secure a barrister from England (10)
I believe the answer is:
obtainable
'this if you really try to secure a barrister from england' is the definition.
The definition suggests a singular noun but the answer is not.
'you can' is the wordplay.
'you' becomes 'obtain' (I can't explain this - if you can you should give a lot more credence to this answer).
'can' becomes 'able' (I've seen this in other clues).
'obtain'+'able'='OBTAINABLE'
'get' acts as a link.
Can you help me to learn more?
(Another definition for obtainable that I've seen is " Can be got".)