TC
This might get complex!
If you go down the road of 'Please name ALL the light and medium twins in the world' that list is not too long.....
We may be able to ignore those .... NOT supported in the UK.
However ... find three or more customers and 'they' will soon find support!
'Eliminate ALL those more than 10 years old.'
That is the ticklish one.... strike the BK117C2 [aka EC145] and the A109 ... But I guess you did not mean that.
Even the 135 and the 900 are on the line..... both are well over 10 now.
So the contenders are I expect the western worlds offerings ... the 109, 135, 145 and 900 plus potentially the 429? The latter being a wholly unknown quantity.
Or did you have others in your frame?
[Spelling checked, not an engineer!]