Unknown color analyzer. Any info or manual?

I got this color analyser (I think that is what it) when bought a darkroom many, many, years ago from an old fellow.

On the front a PM2A is printed, but does not look like any PM2A devices I found on the net.
Manufacturer plate on the back read:
Intrument Number: N313
Made in Great Britain by Medical & Electrical Instrumentation CO. LTD

I need to decide on its use and usefulness, so any further will be appreciated.

Photos:

What I find irritating that as well on the probe as on the main unit there are indicators in the primaries green, red and blue.

The switch on the right seems to be for three paper-channels.
Maybe the respective indicators are for adjusting each channel.

Search for Melico Mk 3 colour analyser, Neil Souch who's a member here has posted some detail of use here. You might be able to get hold of a copy of the manual, another poster in the thread has one.
Ian

AgX said:

there are indicators in the primaries green, red and blue.

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I got the impression that maybe it was repurposed or multi purpose device. If I recall correctly there is actually a light sensor behind the piece of wood you see pasted in the console.

Ian Grant said:

Search for Melico Mk 3 colour analyser, Neil Souch who's a member here has posted some detail of use here. You might be able to get hold of a copy of the manual, another poster in the thread has one.
Ian

Click to expand...

ThanksI I reached out. Hopefully it will give me some idea.

jengel said:

I got the impression that maybe it was repurposed or multi purpose device. If I recall correctly there is actually a light sensor behind the piece of wood you see pasted in the console.

Click to expand...

That might have been for metering in reflective mode, one put the respective patch onto that window.

AgX said:

one put the respective patch onto that window.

Click to expand...

Thank you. I guess the previous owner were not interested in that part thus permanently gluing it shut.