the rover engine number is ground off the block by Caterham to fit the starter motor. they stamp a new engine number of their own on the edge of the ladder frame.
Can confirm most supersports had hydraulic followers, mine did. On my old 1400SS I replaced my standard engine with a race one and this had mechanical tappets.
Supersport cams are the same across 1.4, 1.6 and 1.8 I believe (for hydraulic). I believe the cams for the 1.4 with mechanical tappets was slightly different.
Early 1.4 heads were 'low port' heads which were only on the 1.4. Later the 1.4's got 'high port' heads which were the same as a 1.6 and a 1.8. I would assume most of the head parts are interchangeable though.
Early 1.4SS had cast ali inlet manifolds. Later they got plastic ones like all the others.
check out dave andrews website and the difference in heads