How many hours before the concert starts?

Going to see the Arctic Monkeys concert in O2 Arena on 30th, and I reckon there will not be any seats...(not sure)

Normally how long prior to the concert starts do you go to the arena to queue up? It starts at 6:30pm, at what time do you reckon I should arrive? Thanks

The Vaccines supporting?

Yes. Your seats are your seats, no one else can take them. So arrive whenever you want.

Doors open at 6:30pm I assume, Arctic Monkeys won't be on until around 9-10 so it depends if you want to see the support.

what do you mean you think there won't be any seats? you mean outside while you're waiting to get in...? do you have a standing ticket for the gig? if so it's up to you how good a spot you want to get. i expect there will be lots of keenos queuing from early on in the day, so if you want to be at the front then you should probably get there early in the day as well

If you want to be at the front, you'll either be sleeping over, or queuing from very early in the morning. The longest I've done was 11 hours, but I did get front and center.
Surprisingly queuing for so long isn't always necessary, for Muse once I only queued for about 6 hours, due to the time if took me to get from my house to Dublin, but I was still the closest person to Matt at the entire concert.

If you just wanna go, hang back and enjoy the music you don't need to turn up much before doors open.
If you're really not fussed you could even turn up about 8ish, stay right back, still hear the band very well.
This is what I did for Enter Shikari the other night, because I didn't fancy being right up the front and it was a small venue so I was still really really close.

"I reckon there will not be any seats"

Your ticket should tell you whether you're seated or standing.

Never been to a gig in London, but I wouldn't get to a gig more than an hour before it starts normally.

The Vaccines supporting?