Wherever you go in the world you will find Filipino nurses, musicians, singers, cleaners, etc. You will rarely find a Filipino restaurant. There is a reason for that.
It is an overstay stamp. It says how many days and how much you paid as a fine (if anything). It will cause no problems whatsoever. Here is the one in my passport, never been mentioned on entering;
Search "heathrow arrival assistance". There are several companies offering arrival services from the gate. Heathrow does have its own service but seems not taking bookings after this month for some reason.