Law Society complaints

Can you make a complaint to the Law Society about a solicitor negligence if you found him of this after receiving your file after he has come off record and you find that he failed a breach of an undertaking upon reviewing your file?

An act of negligence and a breach of undertaking are not necessarily the same thing. If you think that there are grounds to suspect/allege either you can complain to the Law Society (see [broken link removed] )

It is not for the Law Society to decide whether a solicitor was negligent this would have to be decided by a court. If you suffered loss as a result of this negligence then seek further legal advice.
If a solicitor breached an undertaking the Law Society can impose sanctions and treat this very seriously. What kind of undertaking did the solicitor not comply with?