Is this a good faulty stamp to have?

Firstly if anyone knows about stamps I have rather a large collection which I bought at auction many years ago which has many penny reds (it has a folder with the words penny red plates)it’s empty but I literally have thousands of stamps which I have never had time to look at so if anyone can recommend where I could get a honest valuation I would be incredibly grateful as they are using up valuable wardrobe space
This is a random one that fell out the wardrobe so I thought I’d get an opinion on it if anyone knows the philatelic world ? Many thanks for looking Jacqui x