In reply to Bertbee:
Great response everyone!
Beyond 'cracks', we just need to rack up loads of routes together, getting used to working efficiently as a team, building belays in record-time etc.
Nothing will come close to actually getting to Yosemite, but there is loads we can do before hand that will work in our favour. Like being a better climber!
Someone had elsewhere recommended camping at a crag for three days, doing ten E1 routes a day, whatever the conditions when we are there. Mostly, apparently, to toughen us up mentally for relentless climbing, even when you are f***ing sick of climbing.
So another question - if you were going anywhere in Europe to do your first ever big wall climbs, where would it be? I've heard people talk of Paklenica in Croatia? Also - has anyone got experience of Cadarese? That looks like a European crack heaven!