never a good idea to get any prescription drug from anywhere but from your gp. Apart from the obvious problems that you can't guarantee what you are getting, it may divert legitimate supplies from where they are needed most.
Eaxtlcy as OTT-Buzzzard has mentioned. the Gov and the department of health recommend dont buy over the net as it may not be tamiflu but something else that may not work.
the only way i got hold of it is by my GP by prescription which had to be taken to an allocared pharmacy who checks the details and only then is it issued. My GP ddint when i had a really bad flu about six weeks agao, he contacted the DOH and they advised him to issue th prescription since im a diabetic and asthmatic.
The most people i fear who may not make it throught his flu are children.
Yes it may cause panic buying, drugs can easuily be forged by false packaging and false drugs. so beware