Help identifying this hammered coin, please: Bhutan ½ Rupee / Ma-tam (or Deb) ND

Hello All! I am lucky enough to have had a hammered coin from Bhutan come into my possession for the lowly sum of 3 NZD. I am, however, having the devil of a time identifying it. I did an image search and it came up with twelve coins. I believe it to be a Bhutan ½ Rupee / Deb, though which period, I cannot say. I will provide links to the top five I think it could be, though in no particular order: 

1. N#47926

2. N#55641

3. N#316192

4. N#235250

5. N#11023

The coin is approximately 20mm in diameter and weighs 4.01 g. It was sold as being copper, but I believe it could just as well be silver, or copper with a silver wash. This one has got me beat, as I find hammered coins particularly confusing at this early stage of my numismatic career. Any help would be greatly appreciated. If I had a gun pointed at my head I would have to choose number 5, though the colour is not similar. Here are the photos of my coin, Obverse at the top:

 Thanks in advance to anyone who can help me identify this coin. Cheers, AY

Your coin is a very nice example of this type, in high grade.  The more modern term for what was formerly called a deb is now a matam. 

I'm not expert enough on these coins to make an attribution, but here's a free article where you might find a match for your coin, 

Coinage in Bhutan by Nicholas Rhodes

http://mms.thlib.org/typescripts/0000/0043/1560.pdf

There is an expert on these called Igor Gusev who posts on zeno and Worldofcoins, not sure he posts here but see https://www.zeno.ru/showgallery.php?cat=7010 there are 5 periods to search through on zeno to see a good selelection

 https://www.zeno.ru/showgallery.php?cat=7012

https://www.zeno.ru/showgallery.php?cat=877

Hi Seeker55! It's excellent to hear that my coin is a nice high-grade example. I'm not qualified to say what that grade might be, so help grading it, would also be appreciated. I was aware that there was a more modern term, so thanks for naming it. Thanks also for the link to ‘Coinage in Bhutan’ which I will read with interest.

 Hello again Vic! I had a quick look at the links, and this appears to be a good starting point for identifying the coin myself. Having said this, I'm as busy as the next person, so any expert who wishes to make an identification for me, will have my deep appreciation.

 Thanks, though, to both of the above members for providing the tools to identify it myself, should the hoped-for expert not appear, as the genie out of the proverbial bottle.

 All the best, AY

Lord, help me! Zeno has pages and pages of these coins that all look the same…

Personally I would grade your coin XF condition. You'll have to match all the details on the coin to make a precise attribution, and this can be somewhat time-consuming. It might be possible to narrow it down to the time period from the general style, and perhaps that is enough of an attribution. 

Thanks, Seeker55, for your grade and advice. All the best, AY

 I've had a good look and as far as I can tell, this coin is not in the catalogue, unless it is one of those without a picture. I shall have to go further afield to identify this coin, but I still hold hope that some expert will see this and offer their valuable help. Thanks to those who already have.

 Cheers, AY

I believe I have made a positive identification of this coin! Before I get too excited I would just like to private message Vic65 (who I have been in contact with previously) to see what he thinks and to convey some other information. Watch this space. AY

While this coin has similarities to KM#3.2, I believe it to be Bhutan, Ma-tam, KM#7.2, B 34.24 (var.), 1840-1865. Copper with silver wash.

This information comes from zeno.ru. I'm happy to be corrected.

Cheers, AY

I have replied to Arthur by PM, 

these coins are a minefield of infinite minute differences so I have advised him how best to contact  Gusev who moderates both zeno and Worldofcoins board for these coins and knows far more about them than anyone.

 Thank you, Vic! I'm much obliged and have returned your PM.

 Cheers, AY

The top expert on the coins of Nepal (and Bhutan) on ‘World of Coins’ and ‘zeno’, Gusev, from Ukraine, had this to say about this coin:

"Bhutanese coin (Period II, c. 1840-1865, Ma-tam).
You have a very beautiful coin with a great design.
It is also an unusual coin.
I think this is … Overstruck on an East India Company coin.
New flans of about 19-22 mm in diameter were cut from East India Company ONE QUARTER ANNA coins and then re-struck for the new Bhutanese coins. Often traces of the original coin can still be seen."

 Further, he had this to say: "Yes, this Ma-tam shows signs of having a small amount of silver. Such coins can be attributed to either Period I (1790-1840) or Period II (1840-1865). The line is not very clear and subjective.
Why do I suggest assigning this coin to Period II?
I see signs of overstrike from ONE QUARTER ANNA coins of the East India Company dated 1835 or 1857. Therefore, Period II is more likely in time."

 He graded this coin as EF-45 or AU-50.

 I have taken the liberty of making one or two small items clearer, in English…

 Anyone can see Gusev's post on ‘WoC’.

My thanks to this expert for identifying my coin, AY