I've been on a few.
Dimitri has several choices on his website both in UK and abroad
www.earthsbeautytours.com
I've been to Tatras, Iceland, Croatia with
www.tatraphotographyworkshop.com and I've booked up with them again for an aurora special in Iceland and a summer tour to Lofoten islands.
These types of workshops are a great way to pick up hints and tips for improving your technique. They also tend to be very friendly and good fun.