Moores and Noell had exclusive rights to negotiate while under the 6 weeks due diligence. I would think that 6 weeks is up but maybe they've had an extension we don't know about or they've already agreed to a deal in principle and are ironing out the details. I would also think that unless there were some demands from either side that could not be agreed upon, M&N are still the only ones who can buy. Unless this deal fails, I don't think the Chinese could swoop in.
That being said, there are sometimes some secret meetings in these things whereby the Chinese could whisper over the bathroom stall, "We give you £50m more!" and then the current board suddenly come in with an unreasonable demand for the Americans and the deal falls apart.