It is true that under JAROPS that 700 hours time is required for single crew operation.
However operators will strugle to find such pilots when the market picks up again and many air taxy operators lose pilots to the airlines at around 1000 hours.
Air taxy operators have successfully used CAP509 pilots in the past you will probably find that providing the operators have a reasonable CAA Ops inspector that they will be granted an exemption to this rule.