Most bus lane PCNs we see are for London using the London Local Authorities Act 1996. This has known defects that have enabled many wins at adjudication at London Tribunals. However your PCN is served under the Traffic Management Act 2004, and so far, we have not seen any defects in the PCN. In addition, we cannot search the statutory register for the Traffic Penalty Tribunal online to see what previous decisions are, so it's difficult, sorry to have to say it. I think you will probably need to take this one on the chin, and grin and bare it.