This article has been released via GizmoChina this morning
Huawei P20 Pro receiving Android 9.0 Pie update in Europe
Whilst this doesn't specifically say when the dates are, the details are on the servers and it seems rolling out across Europe this quarter across Honor and Huawei devices.
As a sidenote, I have reached to Huawei in China last Friday, but as China is on a National Holiday all this week, I've been advised I should have some answers next week as to what is happening in the UK.
Hope you find this article helpful