I wonder if this is a good test question:
John, why donít you come and celebrate with us? We are having / have champagne brought up to our room specially.
Is it possible to see the second sentence as "we have champagne [which has been/was] brought to our room", 'brought' being a participle rather than part of the causative construction?
Thanks. Could you please tell me why we can't see 'brought' as a participle?
John, why don’t you come and celebrate with us? We are having / have champagne brought up to our room specially." only "we are having" is possible.
You just can't [this was, you'll have guessed. a response to the OP] here. In the context of the 'having', the sentence is understood as causative.
You could make 'brought' a participle by breaking the tie between have and brought:
John, why don’t you come and celebrate with us? We have champagne; it was brought up to our room specially.
I see. But why do I have to break the tie? What about
-You told me you're interested in art. Why don't you come round tonight? I have a picture [which was] painted by some famous artist - forgot his name.
It's all a question of context. 'Have', followed immediately by 'painted by...' is possessive (though in 'I have painted tha kitchen' it's not) . In this case, the expectations of the hearer work the other way. If you want to make it causative you can say 'I'm having a copy of a Modigliani painted by an artist friend of mine.'