You can use GB(\s?\d){9}
GB matches the characters GB literally (case sensitive)
1st Capturing Group (\s?\d){9}
{9} Quantifier — Matches exactly 9 times
A repeated capturing group will only capture the last iteration. Put a capturing group around the repeated group to capture all iterations or use a non-capturing group instead if you're not interested in the data
\s? matches any whitespace character (equal to [\r\n\t\f\v ])
? Quantifier — Matches between zero and one times, as many times as possible, giving back as needed (greedy)
\d matches a digit (equal to [0-9])
test it yourself