I have just spent almost a month in the Picos de Europa, re-visiting some of the routes in my book. The first lesson you learn when publishing a guide book is that when it is published it is already out of date. Things are constantly changing. I try to keep my information up to date but it is difficult. So if you are using my book and find any inaccuracies, please let me know. I include updates here, and also in future reprints of the book.
The main thing I noticed on this visit was that the national park authorities have been working hard improving paths. For instance, in Walk 31 there is now a definitive path up the scree slope in the Canal de la Chavida, and in Walk 29 the path towards Jario from Dobres has recently been cleared and is much easier going. However, in that same walk the ascent to Samaya has deteriorated, and although it remains passable it is hard going through scrub which can be chest high.
Any feedback you have from doing these walks is welcome.