I agree. I'll bet there is more than one collector who would fight over the chance to own that engine. Should be worth way more than any possible PM's that it might contain. Try an ad on Ebay, Craigslist, or any antique engine or aircraft magazine or website. Don't scrap it without trying to sell it as is. At least research its value. Even donating it to a museum would be better in my opinion than scrapping it. Of course, it's not mine so you can do what you want with it. Lots of nice history gets junked all the time. You can't save it all.
"Gipsy Six engines remain in service worldwide as of April 2010, Twelve Gipsy Six powered de Havilland Dragon Rapide aircraft are noted on the Civil Aviation Authority register although not all are currently airworthy.[1]"
and
"Today, with de Havilland having long disappeared as a political casualty, very few of these engines remain in use and only a few specialist facilities can carry out overhauls."
Maybe it is wanted for parts if it can't be restored. Won't know unless you check it out. Likely you will find a buyer just after you scrap it if your luck is like mine.