I don't think that's too high considering the amount of work that goes into them.
For an idea of prices for special shapes etc ....... I once had an island top made up (8' x 4') in a kidney shape (it was for a surgeon), for £1400 including a hob cut-out.
I didn't think that was too bad.
Just for comparison, the cost per square foot of quality granite installed here in the western U.S. is $47.92 to $72.15 depending on granite selection and number of cuts needed to install...
Have you thought of using a stone and resin mix like Caesarstone for example? It's much easier to keep clean and wears better. Mine has been in for 13 years and still looks brand new. I just clean it off with a cheapo Aldi kitchen cleaner and it shines like new.