I went through LHR last month. I went through at LHR terminal 5. I am on the way to Basel to see my brother. I passed through at security and I went through metal detector. They let me kept my shoes on and belts on, too. I have no problem with LHR security. I listen with screener.
And coming back home from LHR. I have to change the terminals. I have go to Terminal 3. I took connection bus. I have go back at security again and then went onto the concourse. I passed through at security and they let me kept my shoes on & belts on. I put a small bag in the bin and that's it. I have no problem with LHR security at all.