The pin trackers used in the series are shown using a frequency of "205ghz". Firstly, it should be "GHz"; secondly, 205GHz has only recently been investigated for chip to chip communications or medical uses; and thirdly, 205GHz would be very limited range and line of sight, the signal would be blocked by virtually anything.
The grid reference given to Ros is several miles off the Norfolk coast, in the North Sea. Even if it was a local grid reference, six figures only narrows a location down to a 100m square, which isn't useful in the middle of London.
After Adam calls the ambulance after the failed mugging, his DNA would be on the payphone. Even in 2009 the SOC officers would routinely swab the callbox from which an anonymous 999 call was made.