Minsmere Portrait of a Bird Reserve

As I started another thread a few years about the signed copy Ive got of Minsmere Portrait of a Bird Bird Reserve wuth the signatures of Bert Axel and EricHosking of which I ordered before publication day during the 1970’s. Well I’ve been having a look at the second hand copies of this book as you can normally buy a second hand copy of this book quite easily online. But I’ve a number of signed copies of this same book foe sale of around £40.00 plus. I’ve got my original members enamel badge from much earlier af which the RSPB don’t sell now. But again those members do come up for sale occadionly online. So not that expensive The Ian that works at Minsmere I wonder if you have any idea how many   copies of Minsmere Portrait of a Bird Reserve where actually signed by Bert Axel and Eric Hosking. As I was surprised at how much the signed copies where being sold for. Which seems to sugggest that not many copies of Minsmere Portrait of a Bird where signed by Bird Axel and Eric Hosking: Thanks if you can help Ian!