Setting aside the clear discourtesy, the first solicitor's primary concern was that he could not advance his client's case because of his own undertaking. However, his undertaking had been given after and in reliance upon the defendant's solicitor's undertaking. Therefore it seemed that he could regard himself as able to proceed to enforce his client's judgment as the defendant's solicitor had not complied with his undertaking. It was appropriate to give the other solicitor notice of his intention to do so by virtue of that solicitor's silence. The result of failure to comply with the undertaking was essentially that he had taken advantage of another solicitor who was more mindful of his professional obligations.
Irrevocable authorities are probably in most cases worth the paper they're written on.
Undertakings are important and can be readily implied. Don't just dismiss them. The Law Society of New South Wales is the professional association for the solicitors branch of the legal profession in the State of New South Wales, Australia. 170 Phillip Street, Sydney NSW 2000, Australia.