In the end I googled 'when can I tile onto a new screed?' on my phone in front of them............slow realisation I might actually know a little bit about the trade!
Don't mind me while I bump up some older but good threads. If you can contribute to the thread, go ahead. But if it's nothing for you then don't reply and it'll soon drop off the What's New page etc.
Worth linking to our new forum structure while I'm doing stuff:-