How difficult is it to receive a PU letter

Hi,

I've accepted a job in China as an English Teacher. I've filled in all the necessary forms in (application form, medical check, reference letter, copy of passport etc) and I've had my criminal record, bachelor's degree and TEFL certificate authenticated by the Chinese embassy. I've sent everything to my future employer who is in the process of applying for a work permit and a PU letter (i.e. an invitation letter).

He is confident that he will receive them both quickly and forward them to me. Is it possible to get a PU letter? Or does it depend on the Province? If I receive one is it possible to obtain a visa? I've been searching online and it seems to suggest that U.K. citizens have been able to apply since the 28th of September. Is this true? Or can you only apply if you already had a visa?

Many thanks,
Max