Couple of questions:

“Our owner is low on his UDA's (Units of Dental Activity) which if he dosen't hit, he will lose his £500,000 annual contract”

It doesn’t work like that. If he is 10% under, if pays back 10%. He doesn’t lose his contract.

“I have photographic evidence proving that these fillings didn't take place”

How are you taking pictures of

I find it morally wrong and want to report it, but my colleagues are complaining that they will lose their job via the loss of the contract and I wouldn't want to lose them their jobs. But I won't risk prosecution/fines etc myself for my greedy boss. Am I or any of my colleagues liable for his actions as we all know about them.

Please help, it's quite stressful.