1) Covid shutting down suppliers, manufacturers and container ports around the world.
Some truth in this but now overplayed
2) Brexit - both the obvious, and also suppliers building up stocks for the 2 Brexit "deadlines" that came and went, in case of post-Brexit shortages, which led to price falls due to over-supply, so then Covid lockdowns gave a lot of people the chance to do a lot more DIY than usual at lower prices than usual, so the warehouses emptied and couldn't easily be refilled.
A fallback excuse if I ever heard one.
3) the Ever-Given stranding causing delays to other shipping.
It was a massive ship but it seems to have got 100x bigger and being used as a handy excuse by everyone.
4) HS2 getting first dibs on UK imports.
Another handy excuse but that is not the way the supply chain works.
There are not using bagged cement to HS2!! It all comes from a batching plant.
From what I've been told, there is not going to be a return to normal across the materials supply industry for a long time to come.
Let me rephrase that for you.
"From what I've been told, there is not going to be a return to normal across the materials supply industry until either the supplies have made ludicrous profits and/or the CMA and EU starting fining the bejesus out the suppliers."
FIFY