In reply to ali k:
I'm in complete agreement with this.
Unless van-based climbers staying in Siurana (and to a slightly lesser extent, Margalef) self-regulate, it is only a matter of time before the hitherto extremely tolerant Catalan authorities feel compelled to act.
As Ali says, traveling UK climbers generally make up only a small percentage of these van-shanty towns, but that is no reason to act irresponsibly.
If the situation remains the same, Rodellar-style restrictions are sure to follow — maybe not a bad thing in the long term.
The key-words are respect and discretion.
Pete.