Hi stewa79,
I don't know if this is any help to you..... look at nu-heat/co.uk
Click on Flooring Info. Maybe you could call them and ask about your parquet flooring.
I heard somewhere, that in general, the 'exotic' woods are not great for U/F heating. However one thing I have learned since starting to build is to ask the same question to half a dozen people - I always get different answers. It may well be that the supplier who said that, simply didn't have the expensive exotic wood in stock. I mention exotic, because given that it is old wood it is probably some top quality timber that was used long before conservation measures came into place.
I hope it will work for you, sounds like a lovely floor!