Even if a caution does show up it will not automatically mean you have lossed your job, or won't get a job.
The fact that it was so long ago will sow that you have been law abiding since. The main thing is hat you have done nothing violent in your past, this is what hospitals or employers whose clients are vulnerable look for most.
These days it is hard to say if it will appear on a CRB check. There a series of disagreements on what infomation should be disclosed a short time ago. This led to 5 cheif police officers going to the court of appeal to maintain the right to keep all records of convictions. The police wer then obliged to disclose these convictions o the CRB under part VI of the police act I think. (along those line)
The process of stepping down of convictions has stopped. I do not know what the system is with cautions.
I would imagine that the caution would not necessarily be disclosed, but put through a relevence test. It would be at the cheif police officer's discretio as to whether the caution is disclosed if he thinks it is relevent for the reason for the check..to work with vulnerable people.
hope that helps a little. As you can see it's not an exact science.