Bug: Expression not properly evaluated in RegEx.IsMatch

[Paul [Paradise Solutions]]

Hi all

Was wondering of anyone can help me with why the following expression
works as expected in XMLSpy, but does not in VB.net:

[A-Za-z]{1,2}[1-9][0-9]?[A-Za-z]? [0-9][A-Za-z]{2}|GIR 0AA$

IN VB.net using Regex.IsMatch, all works OK appart from the fact that it
will allow more than 2 characters in the last section. In XMLSpy the
expression is evaluated correctly and shows an error when validating an
XML element. EG.:

Vb.net: AB1 1ABB does not generate an error
XMLSpy: AB1 1ABB generates 'value does not match facet pattern'.

Can this be confirmed as a bug in VB?
Thanks

Paul