I'm not sure if this is the right website for the question, but it looked more applicable here than on https://musicfans.stackexchange.com.
I've got tickets for Billy Joel's concert at Wembley Stadium in London on the 22nd of June. The tickets and the information you can find on Wembley's and the ticket seller's websites say the doors open at 6pm. However, I cannot find what time the main act is approximately starting. I've contacted them without luck so far.
Normally, what time do big concerts at Wembley Stadium start?
I know this depends on the concert, but it would be good to at least be able to have some sort of guideline.