Hi Emlo,
I think that's just a myth that prices decrease I'm Autumn. If anything, prices have never been stronger, but I think that's down to owners being unrealistic with their price.
You'll get the occasional van pop up on eBay/Autotrader etc, but please be aware of the scammers....as the old saying goes "if it sounds too good to be true, it usually is!"
I bought my van in April, and 2 weeks later found it on eBay for 4 x lower than what I paid.