In reply to Stig:
You need to have 4 new ITRA points in one race to qualify, the grading system is a bit confusing at the moment because they are still using the old system alongside. The Ultra Tour of the Peak is 2 old, 4 new ITRA points so it will qualify you for Lavaredo.
I'm running Lavaredo in June, having completed the TDS last summer. I trained for the TDS by running around the Cotswolds and a couple of ultras in the Brecon Beacons. I had already done a tough 100 miler in 2015 and I think having done that one gave me the confidence that I could get distance. The first mountain climb at TDS whipped my arse but after that I got stronger despite the intense heat.
So, if you put in the training and the mountain miles, there is no reason why you shouldn't be successful at Lavaredo.