Rachael ~ That's a good 'find' ~ well done! You certainly have a knack of finding good things! Lt. Commander (later Vice-Admiral Sir) Francis Pridham was given the job of arranging accomodation on the British battleship HMS Marlborough for those members of the Romanov family and many other refugees who were to be evacuated from Yalta in April 1919. They included Dowager Empress Marie, her daughter GD Xenia, and Xenia's children. Francis Pridham carried out his duties very well, and both Marie and Xenia expressed their gratitude to him, although they were both very unwilling to leave at first.
Pridham wrote his memoirs at the end of his career, and that's the book you have found. I thought I had one, but I don't seem to be able to find it today (probably lent it to someone!). I remember it has some folding maps and family trees etc., and some good photos, and tells the whole story of the evacuation. GD Xenia was always fond of Pridham ~ he visited her in England a few times, and she agreed to write an introduction to his book ~ did you see that? John van der Kiste and Coryne Hall use the book as a source in their own biographies of GD Xenia ('Once a Grand Duchess') and Empress Marie ('Little Mother of Russia').
As for the book you have found, for £25 I would expect a nice copy, with tight pages and photos, and maybe a dust-jacket. There are a few copies on the ABEbooks.co.uk site varying from £6 - £35, but some of them sound very tatty. It was reprinted by the Royalty Digest people about ten years ago, and they probably still have new copies, but, if you're like me, you'll want to find a nice original edition......
It's definitely worth having in a Romanov collection like yours, and I've learnt from experience that you have to get these things when you see them. You could go in and, in a pathetic voice, say that you would really love to have the book, but you don't have much money and could they reduce it for you........or, if that fails, you could ask them to keep it for you and then do the washing-up, grass-cutting, car-cleaning etc until you've got enough!!
I hope you get it! Let us all know what happens!