In reply to torbaytradclimber: I was tempted to just put a single two word entry - Hard Rock - in my logbook prior to my MIA assessment, but I didn't in the end.
To be honest don't get too hung up on the logbook. You can have the most amazing logbook, can climb fluidly, competently and efficiently on your personal climbing day but it won't stop you getting deferred on another part of the MIA syllabus. Trust me on that!
They do like to see some big routes on complicated cliffs including those with involved approaches or descents. Stuff on less well-traveled cliffs, especially in Scotland is far more relevant than harder but popular classics elsewhere. However all 30 don't need to be routes like that, 6-10 will easily do, with the rest made up of VSs on more popular accessible crags such as Tremadog or Bosigran.
Here's a list of 30 of the UK's finest multi-pitch outings that would demonstrate a massive depth and range of experience without ever climbing harder than VS:
Wales:
Doom, Craig Cywarch
Kirkus's Route, Craig Loer
Kirkus's Route, Craig yr Ogof
Longland's Climb, Clogwn Du'r Arddu
Mallory's Ridge, Y Garn
Muir y Niwl/Pinnacle Wall, Craig yr Ysfa
Lake District:
Eagle Front, Eagle Crag (Buttermere)
Eliminate A, Dow Crag
Grooved Wall, Pillar Rock
Nor'-Nor'-West Climb, Pillar Rock
Silver Lining, Scafell Shamrock
Sinister Grooves, Buckstone How
Square chimney / Medusa Wall, Esk Buttress
Southern England:
Albion, Devil's Slide (Lundy)
Utopia, Cheddar Gorge
Scotland:
Black Mamba, Creag an Dubh Loch
Cental Buttress (VS Route), Beinn Eighe
Fionn Buttress, Carnmore Crag
Original Route, Old Man of Stoer
King Bee, Creag Dubh
Spartan Slab, Etive Slabs
Scabbard, Creagan a'Coire Etchachan
Shangri-La, Sron na Ciche
South Ridge Direct, Cir Mhor
Sword of Gideon, Sgurr a' Chaorachain
The Chasm, Buachaille Etive Mor
The Clean Sweep, Hell's Lum
The Long Climb, Ben Nevis
The Mousetrap, Creag an Dubh Loch
Wether Wall/Wither Wether, The Cobbler
Hope that is of some use...