I was also interested in buying the 13th edition, however the £22 shipping made it uneconomical and it more than doubles if you get 2 copies so can’t even go halves on shipping with another buyer. I priced it up on the publishers website as I couldn’t find any decent deals on the bay or Amazon. Still waiting to see if any shops decide to start selling it over here.

https://www.bluebookofgunvalues.com/#/Index