It seems highly unlikely that the UK government would weigh in on this issue. However it is outlandish that the cost for a boxed copy of Vista is around double in the UK. If you really want Vista and are not willing to pay over the odds you could always pick up an OEM copy. or use the Vista upgrade trick which has been widely publicised online including in the Windows Secrets newsletter of which I am a regular reader.
http://windowssecrets.com/comp/070201/