If you have undertaken a medical exam in your homeland before entering China on a Z visa to teach, you have the right to refuse a second medical in China, provided that your homeland medical was taken up to 3 months prior to the start date of your employment contract.

Some employers will be offended when you refuse. Usually, they will try to put the skids under you by misinforming you that they can't offer you a teaching contract to sign until you take that 2nd medical, and pass it. That's bullshit. They will delay to put pressure on you. You can hold out, and force them to relent! They WILL relent!

The employment contract will be signed, stamped and 'backdated' by mutual agreement between you and your employer to the date you started teaching, instead of the actual date the contract was signed.

The Chinese medical is pretty comprehensive. To have such a medical in the UK costs a packet as it can't be done on the NHS; or rather it can't be done for free on the NHS. You have to approach the hospitals yourself to arrange appointments for various tests. On top of that you have to get a quote from your GP to do parts of the medical that he can do with the equipment he has in his surgery. It will be far cheaper to cough up in China, so to speak. Having said that the Chinese bosses should pay for your medical but I notice some universities are asking you to get the medical done in your own country, in which case you might find it financially sensible to refuse such a job. We want to spend our first month's salary on beer, fags and cheese, don't we? And not reimbursing ourselves for medicals and visas and such like.

On the other hand, I don't recommend this but ebay sells document stamps.