i want to stay in china for 6 months, i am being invited by a chinese company.

A multiple entry China business visa is proper for you. It takes 4 working days. Documents include an Invitation Letter or a Confirmation Letter of Invitation issued by a Duly Authorized Unit, passport, application form, photo, round-trip flight and accommodation bookings.

Hi Flora, i wont have a return ticket or hotel booking is this a problem? and if i pay more can they do in 1 day?

The return ticket or hotel booking is not so important. The most important is the invitation letter by a duly authorized Chinese unit. Not sure whether the embassy providing 1 working day express service now, but you can get the visa less than 4 working days if you are willing to pay more.

thank u for all of your help uve been great, one last question, im from the uk and will apply in thailand, this is ok right?

If you don't have residence permit or work visa in Thailand, it's impossibel for you to do it there, but you can change to make the application in HK.

i just finished to work with a thai company last week, i have a work visa till end of october and work permit but not sure if company have cancelled yet, is a copy of the work permit ok?

This may be a problem. Even if the work visa is not cancelled by your employer, it is to be expired. You'd better confirm with the visa officers directly before submit yoru application to them.

thank u flora for your help, i have sent an email to songkhla office.

Hi again, is the below enough for the invitation letter?

(company name and all details) are inviting Mr (full name), Male, born on (DOB) , in London United Kingdom to our offices for the purposes of business meetings, entry on the 1st of october for the next 6 months entering and exiting each month over this period of time. We shall bear all expenses whilst his stay here.

(3) If invited by a unit, please provide detailed information such as name of the unit, contact number, address, seal of the unit, and representative or the inviter's signature.

It will be better if you can provide a copy of inviter's business license, order and correspondence between you two.