Temporal Traffic

Lancaster Town Hall (see image) was built long before my birth and will exist until long after my death. Thus, during my lifetime, it is a place that is always there and that I can visit whenever I want to. By contrast, the Time Patrol London office exists only from 1890 until 1910. That is less than a third of a normal human lifespan and an insignificant fraction of the extended lifespan of a Time Patrol agent. Any given agent can visit the office only a finite number of times and it can receive only a finite number of message shuttles. Manse Everard visits the office on at least two occasions, in 1894 and again in 1885 - which contradicts the dates as given above. I think that the answer is that the London office is milieu HQ from 1890 until 1910 but also exists as a smaller local offer before and possibly after those dates. I am still learning about the Time Patrol.

At the end of 1910, there must be a complete record of all the traffic in and out of the office until that date. That record can be recorded on some miniaturized computer unit and copied both to every other Patrol office and to Danellian HQ. The record will show that Everard visited the office x number of times. Therefore, it would break the Patrol Prime Directive for him to visit the office an (x + 1) time. The same principle applies to message shuttles sent by Everard. The only exception would be if he were responding to a temporal change that had invalidated the record.