Stacked turfs

I'd say you are doing just the right thing, so leave the cover on. Just wet them so everything can rot down. In the absence of light (assuming it's black plastic) the grass and other vegetation will die. The worms should do the rest. You should end up with some fabulous soil for potting up. I'd make sure the base is in contact with the ground so worms and other organisms can get into the pile. Give it a full year.

Thank you. It's covered with blue plastic which is quite thick and stacked onto the soil. I shall get the hose out and give it a good soaking.

I use a plastic cover over turfs but don't bother about the sides. Grass and weeds do sprout out but is an easy matter to trim them back occaisionally.
Regarding having the base in contact with the ground; this is OK if the ground is clean. If there is couch grass or Bishop Weed in it the roots will invade your stack and be difficult to remove.
I would have thought one year was a little early to expect good loam, Bertie, but I have been fortunate enough to have enough stacks over the years that I don't have to touch them for several years.

Mine are still not broken down and it's been two years.