212man, without splitting too many hairs over this, what the UK calls a GPS Approach (RNAV or RNP .3), doesn't quite qualify with standards in the rest of the world.
The UK GPS approaches do not provide guidance for the missed approach segment. It is either climb straight ahead and ask center for help (Gatwick, Heathrow, etc), or "LCTR required for missed approach" (Gloucester, etc). A good FMS system should be able to provide constant overlay information, but compared to what's going on this side of the Atlantic it looks bush league and half-hearted. If it is any consolation to UK pride, the Norweigans have a similar restriction on their LPV (localizer precision with vertical guidance) precision GPS approaches, and also require conventional navaids for the missed approach segment.
Must be something regulatory over there, and maybe somebody has some explanation. We're busy decommissioning NDB's, Marker Beacons, LCTR's, VOR, Radar etc. here, so designing a new procedure requiring existing ground based navaids seems pointless to us.