While your experience certainly sounds unpleasant, how can you be sure that the non-revs weren't, in fact, deadheading?
As you know, deadheaders take precedence over revenue pax, since without crew at the out-stations, those flights could not be operated.
Also, as a side note, to me the most unpleasant aspect of T5 is the virtually constant epic line at security, which, interestingly, was rarely a problem when B6 operated out of T6.