I bought both my large bays at CO outlet around May/June this year. The original price on them was £695 and the outlet price was £486. I was lucky and there was extra 10% discount due to a promotion which brought them down to £437. I got a Chocolate and an Oak but the SA said they'd had black as well.
There was definitely a chocolate in the summer sale there but I didn't check the price to avoid any regret!
Looking at website measurements I'd say the large bays is a bit smaller than the piccadilly but it's still a big bag. I use my chocolate as an every day workhorse. With two children under 5, I carry loads and get everything for the three of us in it. Looking at pictures of the piccadilly, the handles on lge bays appear longer as I can carry mine on my shoulder. Hope this helps.