my very first live gig was a thrash metal band, I was prob 15 yrs old & my then boyfriend was really nervous about me getting knocked over & crushed 
vbus, glad you managed to get your tickets
sfx, C&C was busy but not overly so, easy to keep an eye on everyone, think as the weather was so mild everyone was more wandering the gardens
Re Harry Potter, I can only do evenings, earliest probably 7.30pm, but if everyone would rather do daytime/earlier then go ahead