As always, ask your printer first, but for some background:
Unless your printer is printing direct to media, it's highly likely that the prints are going to be mounted to some kind of substrate. That requires additional bleed, as the print can shift about slightly as it's being mounted down; the larger the print, the more it may shift. For panels that size I'd say 15-20mm bleed would probably be fine (you can never really have too much bleed).
If you're having a wrapped edge, don't forget to add the equivalent thickness of the material to your bleed; so if it's being mounted on 5mm foamex with a wrapped edge, you'd want 25mm bleed (20mm + 5mm). People forget this all the time. I've seen my fair share of artwork intended to wrap around 25mm substrates but they've only given me 3mm of bleed to work with.
Also, unless your printer asks you to, don't include crop marks. If you do get asked to include them, be sure to offset them so they're sitting just outside the bleed, not it, otherwise they may show up in your finished print.