I have to say i was allways puzzled about the use of radar headings within the UK. Our flights from stansted to glasgow, manchester or even belfast were quite often completely on radar vectors from shortly after take off until the ILS whereas domestic flights within germany or spain are usually done using directs or flight planned route until within the TMA of the destination where radar vectors are used for positioning onto the approach.
That said i allways felt safe that way as the ATCOs are obviously knew what they were doing, it just was a source of conversation on the flightdeck as it is unusual when compared with the rest of europe.