SASLESS
From the report - The pilot was given a clearance through controlled airspace via the london eye enroute to his destination which was not in the London City or London CTR. The minima regarding aircraft inbound or outbound from an airfield in the zone therefore did not apply. He was give a choice between VFR or Special VFR - this allowed the pilot to comply with either criteria. He was given a maximum altitude to fly in the zone.
You can see from all CAA publications and the AAIB report that the route was in CAS and a clearance was given. It is the responsibility of the pilot to advise if he cannot comply with the clearance and relevent parts of rule 5. The report also shows that the controller asked the pilot if he wanted an IFR clearance - the pilot declined this opportunity and said the he was VMC" on top" - given the weather reports, this did not necessarily mean that he was not complying with the VFR.