cavgirl is absolutely correct, context has a huge effect on how an individual perceives colour so you need to choose your mint with the other colours and lighting in mind.

Also, you cannot depend on choosing a colour using a computer screen unless the screen is calibrated to the same colour space as the item you are looking at. If you put two uncalibrated screens of different makes next to each other showing the same item, the shade will vary between the two.

Swatches are a better bet but only if they are made with the actual paint and not printed. Otherwise try sample pots to actually put the colours in place to see how they are when dry and with the same number of coats as you intend to apply when you do the job.

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You are welcome, here http://www.britishstandardcolour.com/  is a link to the British Standard colour charts The BS4800 has the best selection of greens. These charts used to be available from most professional paint suppliers and all of them could be made up on the colourmix machines.

I am a little out of date on what is available in the UK as I haven't lived there for 18 years but the BS colours should be current.

The final three so far are:
Amazon Jungle 6

Peppermint Beach 6

Japanese Maze 5

Anyone love or hate any of these?

Also, I discovered that the original inspiration was an American brand ("Lullaby Paints") in their color "Bengt". Any ideas of how I could find out the best UK match?

e-paint gives alternative colours and rates how well colours match, don't know if that helps?

I used a true mint named seafoam in my bedroom by Dulux. Valspar also do a lovely mint also called seafoam.

When putting paint samples on walls make sure that the background is white,otherwise a colour no matter how slight will taint your sample,also always put at least 2 coats on ,with so called Designer paints (F&B etc) at least 4 because they don’t cover,I have been doing using the above method every working week for over 40 years ,make sure your sample is at least 12 inches square to get a decent representation.

I agree that trying testers on a white wall is best to get a true colour, but the only way you will get the exact colour you want is to mix testers plus white paint. Make sure this is on a sheet of white artist paper. When you have the exact colour take it a shop where they will match the colour exactly. I did this with artists’ acrylics and took it to a Dulux mixer at Homebase. So many people have admired the green of my front door and it was the only way I could get the colour I wanted. Good luck!