The process of turning opium poppies into morphine:
About three months after the poppy seeds are planted, brightly-colored flowers bloom at the tips of greenish, tubular stems. As the petals fall away, they expose an egg-shaped seed pod. Inside the pod is an opaque, milky sap. This is opium in its crudest form.
The sap is extracted by slitting the pod vertically in parallel strokes with a special curved knife. As the sap oozes out, it turns darker and thicker, forming a brownish-black gum. A farmer collects the gum with a scraping knife, bundles it into bricks, cakes or balls and wraps them in a simple material such as plastic or leaves.
Then the opium enters the black market. A merchant or broker buys the packages for transport to a morphine refinery. "Most traffickers do their morphine refining close to the poppy fields, since compact morphine bricks are much easier to smuggle than bundles of pungent, jelly-like opium," writes Alfred W. McCoy in The Politics of Heroin.
At the refinery, which may be little more than a rickety laboratory equipped with oil drums and shrouded in a jungle thicket, the opium is mixed with lime in boiling water. A precipitate of organic waste sinks to the bottom. On the surface a white band of morphine forms. This is drawn off, reheated with ammonia, filtered and boiled again until it is reduced to a brown paste.
Poured into molds and dried in the sun, it is now morphine base, which has the consistency of dense modeling clay. Morphine base is smokable in a pipe - a practice introduced by the Dutch in the 17th century - or ready for further processing into heroin.
It seems an out building or the like would be required. I believe the raid team searched all the out buildings but you say some raid team witness statements haven't been released.