I've just seen in a Sutton's catalogue, wooden plugs which have been
impregnated with mushroom spores.
It says to drill holes in freshly cut logs (not pine) and insert the plugs.

Just so happens that I'm partway through butchering a cherry tree so have a
supply of logs.
The plugs are nearly £12 for 60. I don't mind parting with the £12 if I get
a good crop but may need counselling if I don't.

Any experiences or advice?

mark