Bonjour,
If ypu look for boilers for boats, in France, we know JMC, I have plenty of them, exemple :
I also have JPB boilers, example in my tug JAN with a D10 he restored for me :
Or Pendlesteam in England:
My Kingdon also from Nigel :
And I note that they are cheaper than Stuart. packaging costs are the same for all the manufacturers I imagine.