The estimate of 15k then realised price of 2200 would make me think others weren't convinced

I too would like to see them.
Ive asked him to message the seller and try to get them!

That would definitely help.

You'd think the seller would have known it's worth though! Why sell so cheap? No reserve?

The rug didn't do so well either.....

I thought I'd seen this before on a well known online auction site ending with "Bay" and starting with "e".

there were lots of questionable items on that invoice, 2 chihuly and 2 tiffany lamps. A lot of items people did not seem to think were on the up and up. Your buddy paid a bit more than i would for glass "in the style of" or he got a truly remarkable set of deals that day. Id love to see some pics of those. very hard to authenticate good glass pieces by picture, but if they are obvious fakes would certainly put the whole batch in question.

One presumes the better answer for him is to get a good insurance policy that will accept these appraisals and then have an incident in about 10 months.

Not to pile on, but i do find the hand written letter interesting.  For me i would give zero value to the letter or photographs unless they can be matched to banksys website.  BUt it does seem to create an interesting idea.  In my mind a stolen street piece from any artist is worth zero, because i would not want to display a stolen street piece....but.  If you are looking to run a real number on folks, one supposes cutting some banksy stencils, throwing them up in some random alleys, and taking some snaps before and after is bound to fool at least one person with more money than sense.  Adding some little touches that i wont mention to give it some street patina and a goofy hand written note.  

Thanks!
Just gotta find this thread.