In reply to samben6:
I haven't been to Melloblocco but I have been to the area for bouldering last year and am going again this year for most of the spring, so I can answer most general queries and some Melloblocco-specific questions to the best of my understanding.
The event is held in the Mello bouldering area, described in the Mello bouldering guide book, which encompasses 3 connected valleys: Val Masino, Val Di Mello and Valle dei Bagni. There are many sectors in each of these areas. Every year they open new boulders and new bouldering areas for the festival so there are fresh problems for the competitions.
Regarding transportation, even without the festival, you do not need a car for the bouldering in the valley. For the festival they specifically discourage cars. You can reach the valley from Milan via train to Morbegno, and bus to San Martino, which lies at the top of the Val Masino. There are accomodation options (limited and can be quite expensive) or camping in one of the campsites.
Flights to Milano are very cheap from UK, and if camping the whole trip could be done on a small budget, especially if not renting crash pads due to the festival.
I cant speak for the activities at the festival, but I do not think that every attending is doing the comp or is some pro athlete. From what I understand, it's a more complete bouldering festival for everyone with a comp for the strong.
Speaking for the area, in my opinion it is one of the greatest bouldering areas in the world and is superior to many more well known and popular areas in Europe. The abundance of incredible lines, especially if you climb around 7a-7c, is truly incredible. In addition it is without a doubt the most beautiful area I have bouldered in.