Silly question but what would the equivalent of simple green be in europe?
I'm not sure, but in England I've used pure Dettol and Fairy Power Spray.
Pure Dettol is very strong, and can soften greenstuff and superglue and even plastic bases if the model is left in it for a long time; use this if you really want to start fresh.
Fairy Power Spray is much softer; it takes a lot more work to strip a model with it (I find that taking all the paint off with it takes many cycles of spraying it on, brushing the model with a toothbrush to get the spray to "bite", then wiping off with a kitchen towel), but the advantage is that it has much less effect on superglue and greenstuff, so it's good for taking the paint off a model that you don't want to disassemble or have to re-sculpt. HOWEVER a few years ago I heard that they changed the formula so I don't know if it still works now (I haven't had to use any in a long time so I haven't needed to buy any since hearing about the formula change).
They might be able to help. Go with the original version, that’s what we use in the States. I have no idea how much it will cost, but I’ve got a couple of small glass jars full of simple green that have been reused so many times that they are now a murky brown like swamp water.