Thanks K & CM for the advice. Just a point of detail - where do the Y and Z go in the FPL - e.g. if my routing is (EGLK) DCT SAM DCT MP with the change from IFR to VFR happening after SAM?
I have only filed VFR flight plans so far for trips outside the UK - I always thought it would be prudent to do one in the UK if you were flying over mountainous terrain or sea, but I had assumed this was just so S&R could be alerted if you fail to turn up at your destination. Seems like this is a good assumption if no-one enroute gets it!
Phil