We have been using SMS for dynamic password sign-on over the internet for more than a year for similar systems to that mentioned in your article without any problems, including SMS ordering (Message in a bottleneck, letters.computing.co.uk).

Are the problems experienced by your correspondent, Andrew, confined to his mobile phone company, or are the delays at one or more particular SMS-originating mobile phone companies? It would be very
interesting to know.

Name withheld on request