If the amount of interest is over 100Euro then they are obliged to account to their client for it. However you should be aware that ordinary current accounts ( which the client account normally is) have a nominal interest rate and unless the sum is very large the interest might not have reached this amount. The solicitor is not obliged to put the funds into a deposit account unless asked to do so by the client and even where asked to do so, would be entitled to charge an administration fee to do this, and again unless the amount is large and the interest rate on the deposit account good enough, one might cancel out the other.