Like Life's a Beech, this is what I do for a living. The Jar Ops 700 hour requirement is for Commanders of aircraft that would normally require a type rating but that have been certified for single crew ops.
For commercial single pilot light multi IFR you must have a CPL/IR and at least 50 hours multi IFR of which at least 10 must be P1. If you read Jar ops carefully you will understand. This has also been confirmed by our CAA AOC inspector.
Now to the real world...All commercial operators work to the rules laid down in their own particular Operations Manual. Some of these prefer to adopt (quite rightly, in my opinion) the more restrictive pre-entry requirements of 700 hours, 40 PI multi IFR in order to minimise the amount of training that would be required to get a new pilot on line. At my company a new pilot would be given max 3 hours' practice on the aircraft before having an OPC (IR Exam). This would be followed by 20 sectors of line training before being sent off alone across Europe alone in all weathers and mostly at night.
Air Taxi/Charter in light twins is a small industry in the UK. Unless you have plenty of unusual flying in your logbook, a lot of actual IFR and some decent contacts you would stand more chance of landing a sponsored position with BA than succeeding via this route.