Might be worth looking at the MI (manufacturers Instructions) for the AirCon unit.  SY is an absolute no from me but H07 flex does have its merits when doing a Aircon unit.  Worth looking at the inrush current for the AC if you are swapping out the CU/DB as they will normally require a longer tripping curve provided by a C type or D type breaker. Also check there is a local means of isolation which can be locked off for maintenance.  As always use BS7671 to guide you and remain compliant. 

Depends on the environment - would T&E or NYY-J been acceptable? The wiring regs used to have a prohibition on the use of flex for fixed wiring but that went the way of the Dodo several decades ago. If anything H07RN-F is probably a little tougher than equivalent PVC sheathed cables. Black sheath is probably a benefit if exposed to UV. A lot of aircon installations I've seen use SY, so this might be an attempt to comply with standards a bit more.

So does the environment require armoured (presumably not buried in the ground) - is there a high risk of mechanical damage?

RCBO - not usually required for fixed equipment (unless in bathroom etc), is the cable concealed in a wall anywhere? or is it a TT system?

   - Andy.