Hi there - its me with my first set of questions

Other than my rusty boot floor that has gone right up to the arches I have a few other problems and wondered if they are common

My central locking works fine as do my interior door handles but my outer handles on the front dont seem to want to open anything anymore but they did when I brought it !

Also is seems the previous owner bypassed the heater matix - is this common for any reason / is it easy to get to etc ?

Thank in advance