Yes, there'd be a need for extra cross-bonding and the 0.4 sec. disconnect requirement might necessitate the use of an RCD (GFI), but there's nothing in the IEE Regs. to specifically prohibit the installation of a washer or dryer.
The only prctical restriction I can see here is that some bathrooms are just physically too small to achieve the required 2m (6' 6") separation from the tub.
