For sure, the transistors could have come from anywhere.
I personally believe calculators are the most likely source for the reasons I describe below.
My understanding is that the later GEC was a huge corporation with multiple locations, but the earlier Marconi-Elliott only made this type of semiconductors in their factory in Witham (that looks to be some 100km from Elstree studios) and only during 1968-1971. When in1971 M-E were merged into GEC they stopped the semiconductor production and closed the factory.
So, by 1976 I guess they could be found only in junk or some surplus (which was practically also junk because they became so obsolete just for few years).
That could include prototypes of devices that were still lying around in that other GEC facility close to Elstree, it is a very interesting possibility. Maybe the a prop guy met one of the GEC engineers in the local pub and asked "Do you guys have some junk electronics that we can use for our props?" I mean you never know how things could have happened so many decades ago.
We don't see much electronics used in the props, unlike the jet engines, the Michell and V8 parts that are all over the place - so probably they didn't get a large pile of electronics scrap (if such a thing existed back then) to scavenge, but just some random device or pieces.
But, if it was an obsolete or defective device that was just lying around at the time, it should be a very short list of possible sources.
Let's say once these semiconductors available on the market it takes an year or two to design and produce some device that uses them. That leaves a very short window of probably 1969-1972 that any devices that use them were made.
We know so far that they were used in the calculators, some obscure early British computers, the DAT11 was in a TV and I won't be surprised some were used in military electronics. Add to this some fancy (for the time) radios maybe and I can't think of any other common device in the very early 70s that would have advanced electronics in it.
These bulky calculators with limited capabilities were for sure junk by 1976, totally obsoleted by the pocked sized ones like the Exactras. TVs made in 1970 might still have been decent in 1976 I'm not sure, but they tend to have longer upgrade cycles and the military stuff as well.
So that's my theory, and that's all it is - just a theory.
Without a doubt, the ones found in the Anita are the correct ones, and I've not been able to find an example of any other device from the time that has the same ME decals.
I just found it to be such a crazy coincidence that there was a Marconi building in such close vicinity to Elstree studios. It just made me wonder, did they come from a dismantled Anita, or could they possibly have come from a box of surplus parts that somehow found their way to the prop department?
I guess we'll never know for sure.
I do like the pub idea though!
I know this is a way long shot and very late to the party, but is there any chance of parts available to purchase? That's if there is any left over.
Hi there. Thanks for asking. As of right now, there is actually one full hilt available. I'll send you a DM with the details.