I also have the excellent book - it was me who started the thread!!! But name changed with the BBS move! Dont look upon this as a cheap option as even with all the facilities some of the materials arent cheap. Try looking at the price of the 1 inch square brass about 7 inches long used to make the breech block! Then you have to buy a barrel and unless you are clever at woodwork a stock blank £60 or one off another PCP - I actually bought a s/h Storm for about £100 less than I estimate my finished cost! Oh and the book is £30 The book is truly excellent and easy for any one competent at metal work to follow and build.
Best of Luck