Heres some news on my search for a match to the original varitone 2-tone Grey colours:

Lou shorten kindly sent me a colour swatch for Twilight Grey (GR9) and Birch Grey(GR3), which I had analysed at AZCO NOBEL at 136 Milton Park, Didcot, Oxon, the results are recorded on their database.
 
The paint is Sikkons / Lesanol LES2K formula as follows:
 

TWILIGHT GREY GR9

Colours scanned: AZKO NOBEL

136 Milton Park, Oxon

Paint: Lesanol

LES2K formula

Colourants

Conc,(g)

Cumul.(g):

%

1

21

410.20

410.20

0.404

2

11

69.30

479.50

0.068

3

22

199.10

678.60

0.196

4

65

337.80

1016.40

0.332

Quantity: 1.0 litre

1.000

BIRCH GREY GR3

Colours scanned: AZKO NOBEL

136 Milton Park, Oxon

Paint: Lesanol

LES2K formula

Colourants

Conc,(g)

Cumul.(g):

%

1

11

694.40

694.40

0.583

2

32

4.00

698.40

0.003

3

52

7.30

705.70

0.006

4

22

180.20

885.90

0.151

5

65

304.20

1190.10

0.256

Quantity: 1.0 litre

1.000

 
The colour swatch they provided, matches the original perfectly and I have given the paintshop the go ahead to use this, and expect a superb result. I shall try to get them to provide 2 large swatches that i can cut up if you want one.
 
By sending a sample (small bodywork section) Azco Nobel can scan / analyse any other Magnette paint colours. (a polish lady with a name i cannot possbly remember was extremely helpful)
Look here which colours were used on Magnettes.
Any queries, Azco have the GR3 & 9 on their database (a test-piece should be recommended firstly though as i am not responsible for any errors in quoting the above!)
 
The above formulas should allow any bodyshop to mix up the correct paint using modern materials.
 Peter Bonthrone, UK