Here we go then, let's play top trumps with capabilities:
Tornado GR4
Armament: Storm Shadow, Brimstone, ALARM, AIM-9 Sidewinder, Paveway II, Paveway III, Paveway IV, Enhanced Paveway, General Purpose Bombs, Mauser 27mm
Tac Recce: RAPTOR & LITENING III
Harrier GR7/9
Armament: CRV-7, AIM-9 Sidewinder, Maverick, Paveway II, Paveway III, Paveway IV, Enhanced Paveway, General Purpose Bombs
Tac Recce: DJRP & Sniper
...and the result? Tornado GR4 wins with superior RAPTOR, Storm Shadow, ALARM and Mauser (all the rest are "evens" between the two). The only advantage for GR7/9 would be CRV-7 (did they ever field flechette?) - VSTOL is "evens" with Tornado's Mach 1.2 to Mach 1.4 capability. Also GR4's night low-level IMC capability is pretty unique.
So when the Airships and Admirals played "top trumps" for SDSR, I suspect the right platform won.
LJ