theres no way there going back to sand and cement
the adesive reps have all but brain washed every bugger in to thinking they know best
well ive got news for them and you they dont
The 3 porblems with d&d are.
1. The risk of exceeding the bedding depths. 6/5mm, 10mm in isolated areas. this can result in the adhesive exsesivly shriking. As I said I looked at a failure yesterday of 800x800 tiles on a wall, where the thick bed of d&d adhesive had shrunk, and caused the tiles to debond.
2. You need to make sure you're getting 100% (or there abouts) coverage in wet areas, and 80% elsewhere. This is to be able to support the weight of the tiles.
3. The BS says weight limits of 20kg psqm on plaster, if you have a 12mm stone fixed to 5 or 6 dabs of adhesive, then you are far exceeding your weight limits.
If you can d&d, and overcome those REAL issues, then good luck to you. I'd rather see the walls made good, and serrate away.
This isn't from an adhesive rep. Its from a tiler of 10 years, who as always seeked to improve his knowledge, even if it means eating a few large slices of humble pie. Which i have done, and continue to do.