Hi my dining room PIR has started draining the 3v batterys completely within a month so looking at replacing it, seem to be able to get hold of one for circa £15 and the alarm company unused for the original install want £110 all in. I have the engineer code how hard it is it to learn in a new PIR not able to find any info on it really I guess it's just a case of pressing a few buttons in sequence but without the correct information in stuck. Any help appreciated.