I am an EU citizen. From 2008 until Dec 2015 I lived in the UK, first as student, then employed. My understanding is that after 5 years of residency in the UK, I automatically acquired a permanent residency right analogous to indefinite leave to remain (ILR). This would be lost after living elsewhere for 2 years, ie at the end of this year.
Now I expect to start a permanent job in the UK in March 2018. Given the Brexit-uncertainties, it seems very desirable to retain my ILR.
So my question is: What exactly counts as moving back to the UK for the purpose of retaining ILR? Would say getting a flat (and paying council tax) this year suffice, even if I spend most of January and February elsewhere?