Hi Janey,
High Street as you originally thought is a restricted zone, with parking only available for disabled people within certain areas and with restricted time access, but due to the limited powers of the Civil Enforcement Officers, the new name for traffic wardens, who are only able to enforce non moving traffic offences, i.e. parking, vehicles can pass through High Street and exit through Abbot Street via Town Hill without fear of receiving a penalty. The bus lane is a joke as bus services no longer service the High Street as a by product of the pedestrianisation scheme which reduced the width of the highway. Police officers are the only ones that are able to enforce illegal entry into High Street and due to lack of resources it seems that they are unlikely to be available to enforce the Traffic Order at this present time. I hopes this clears up your query,
Regards,
JOK