Dear Toolate ,
following changes to the law this May , cautions more than 6 years old will be filtered off under amendments to the rehabilitation of offenders act so that you do not need to disclose them on job applications (unless high security e.g. police, MI5 etc), and they will not come up, even on enhanced CRB checks
However, certain serious crimes are excluded so that a caution for supplying drugs would be on until you were you could show specific circumstances to remove it.
However, possession is not on the list of serious offences published by the disclosure and barring service. It is almost certain therefore that you will be in the clear on this, but,please be aware that the DBShas been given by the government a secret list of 4000 offences which are not on the public list, but which could mean that it is on the secret list of crimes, that it can still remain on. There is confusion caused by adverse and a lot of pressure on the government's the published list which hopefully will be done in a few months time. In the meanwhile if you wish to be absolutely certain. You should email the D BS enquiry line for them to confirm that your matters are not on any secret list.
Regards
David Wacks