Jason,
I have followed up on the lost wax firms you supplied. Only CRO have replied so far. It seems CRO use a 3D printed wax technique similar to Sculpteo. They get the work done in NZ and ship the completed items to the UK. At the moment CRO have only done brass/ bronze castings and are checking if aluminium is available from the supplier.
Unfortunately Sculpteo no longer offer lost wax aluminium, it may have been a process problem.