The only difference between a German invasion in1944 and what is happening now is the Germans had guns and we wouldn't have put them all up in hotels while they tried to take over the country.
they don't know most of them are in the country and those they do it takes years to process their applications. Meanwhile communities are suffering massive disruption to their normal lives by hordes of people who shouldn't be in the country take up every possible form of habitation at tax payers expense. Have you read about the illegals who have committed a serious crime including the murder of an old man? A minority I agree but they should never have been allowed into the UK.
Get the required documents from your landlady, house books, ID card etc and register her at her address on the system. Then add your address as her rental property. Then you can upload your passport and register yourself at your address whenever you want. 90 day report is quite easy to do on line after the first one but do the tm30 first. It does not matter how many tm30s have been done while you travel as long as the latest one matches up when you do 90 day report. This is what I do now and it takes about 5 minutes to do both and saves my landlady a lot of grief!