I would agree with what Warwick is saying about the fallout from Brexit - none of us know what will happen and it may be that different countries approach a new relationship with the UK in totally different ways. Having said that, you obviously have experienced living in another EU country and have decided to give living in Crete a try so:
Sitia is a fairly small town. The relationship between local people and "foreigners" of all nationalities is generally good - maybe because there are not too many of us
We have lived here for 10 years, and have found, overall, that the local people are more than willing to help, and dealing with various officials seems easier, overall, than is reported on this forum by some of those living in more populated areas.
Unlike more tourist orientated areas, Sitia is "open" all year round - one of the reasons we chose to live here. Most of the restaurants close in the winter, but the larger coffee places remain open, and sitting in a harbourside cafe with a log fire burning watching the world go by on a winter morning is wonderful. You will find that the majority of local people have at least some connection with olives and the harvest takes up a good deal of everyone's time between November and January, so don't expect anything to happen quickly during that period.
In line with the general thinking on the forum it would seem sensible to rent, initially, until you are sure that this is where you want to stay, although there is plenty of property for sale around - for instance, many British people I know have gone back to the UK for various reasons (though mainly to do with health). What the market in Greek owned property is like I have no idea, but I suspect that there are a good number of houses for sale in that sector as well - http://www.greekbay.gr/properties/
would indicate that this is the case.
As in all things - whatever you do, find yourself a good lawyer and accountant, and don't be pushed into using one recommended by an agent!