Thanks for all the info guys!

A few guys have mentioned 1/30th and while if the climber was stationary it'd be fine but seeing as how I'm wanting to get action shots as another has mentioned I'll have to take it up to the sync speed.

DOF shouldn't be a concern at the distances I'll be shooting from either and my lenses probably aren't going to allow me to get really shallow DOF anyway.

Thanks for the link to strobist too! I actually thought about picking up some ebay triggers but I'm not going to have enough time to be comfortable and confident using them so I ruled it out for now. It will be on my shopping list later on though

Thanks for all the help guys! Fingers crossed, I'll post up the results after the shoot.

Cheers,
Mike.