Did you sign a full and final settlement agreement?
Also how long ago was the original claim?
If you did not sign a full and final settlement and depending on time scales, you may still be able to make a further claim, but you would need to qualifiy why you feel the settlement was too low and why you subsequently agreed to that sum in the first place.
You should have been advised at the time the offer was made, so are you suggesting that your advisor was negligent as well?
It could be a can or worms you are opening up depending on the facts.
