[kvinchuca]

You are correct in saying that there are examples of shop about. What I stated in the first post was there is no governing body who can arbitrate on usage or in fact definition.
The benchmarks we took as a near a standard as possible were two of the biggest selling and most used dictionaries in the English teaching world. The Oxford Advanced Learner's Dictionary, and the Cambridge Online Dictionary.
Both agree with shop around, but neither give shop about.
Thanks for comments and interest
Regards.....kvinchuca