ZOOKER
'a), On its own navigation to an exact reporting point.'
Yes, the centrefix.
'Send an aero to the 'centrefix' and ATC has no idea where it is going, unless of course the centrefix range is specified in the clearance.'
You have solved the problem.
'who is responsible for terrain clearance here?'
ATC still.
'what is the RTF failure procedure if the a/c has passed abeam the normal clearance limit?'
New clearance limit replaces the previous clearance limit, as usual.
See AIP, STAR chart, MATS pt.2 for RTF details.
Define normal clearance limit...
Can be a grey area. With a few questions, though, where is it geographically, what altitude do wish to be at over the centrefix, it can be a useful technique.
As far as ATC are concerned, there exists an approach, and a centrefix.
Centrefix approach does not exist.
But is it centre fix, centrefix, or centre-fix?
(Just don't spell it centER) !!!!!